Tower's Growth

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All towers gain experience, and in turn gain levels. Towers grow over time and thus become something more powerful than what you originally built. Each tower grows in a different way depending on their Growth Rating. The general rule of thumb is that when a tower levels up, it's usefulness is multiplied with it's growth. A tower with a 17.5% growth rating will then become 17.5% more useful. Each level this compounds so a level 10 tower may have grown to 5 times its original power.

Every time a tower gains a level it receives one point to spend on various abilities. Most towers which have a natural attack have access to increasing base damage or attack speed up to 15 or 4 times, respectively. Other towers may have auras, spells, orb effects, custom abilities, or many other types of abilities to improve. Not only does the tower gain abilities but the tower's worth in gold also increases. While you may have paid 400 gold for a tower, it may be worth 1500 at level 10 giving you more gold back than what you paid for it. Tower's double as investments. I've also considered the possibility of a tower with a very very low base rating but extremely high growth rating. Such a tower would act as a very good investment, because it's resale value will grow quite a bit over time, much more than any other tower, but it's actual damage won't ever become significant.

To balance the growth rate of pure damage towers with towers that use abilities, all spells are created on the fundamental idea that every one mana used should yield approximately 2 damage. This isn't always the case though when dealing with abilities that slow, stun, or disable enemies. As you level up the ability, the mana cost and damage increase while the cooldown decreases. The actual values of the spell have little bearing on it's potential power. Instead the damage of a spell is controlled completely by the mana regeneration of the tower casting it.

Every time a tower gains a level, it's mana regeneration increases. If the tower uses points to upgrade spell abilities on it, than the mana regeneration further increases. A general rule of thumb is that the mana regeneration limits a spell at first, but after gaining a few levels the cooldown then limits the spell. As a result, a tower must invest multiple points into a spell (raise mana cost, raise damage, lower cooldown). Getting one point in a spell will not yield maximal damage. Typically upgrading a spell every 4 levels is required to maintain it's usefulness.

While a high growth rating (say 17.5%) would obviously make a tower better in the long run, it doesn't necissarily mean a tower is better than another tower. Each tower also has a Base Rating which is a measure of how useful it is compared to it's Gold Cost. A tower with a 90 base rating and 17.5% growth rating at level 1 is much worse than a tower with 140 base rating and 10% growth rating. Infact, the 140 base rating tower will be better until both towers reach level 8. Higher growth rating yields more potential late game. Higher base rating yields more potential early game. Ultimate towers (accessed via specialization and research) tend to have high growth ratings and base ratings, making them powerhouses the moment you get them.

Spell Abilities

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Most towers have some sort of spell they can learn to use to help against enemies. Some spells are very similar to basic Warcraft III abilities such as Storm Bolt, Thunderclap, or Flamestrike, while other spells are more customized and unique. Fortunately for the player, I intended for these spells to not be a hinderence on the player. That is why I brought to life a sophisticated Autocast system to micromanage towers while the player focuses on building, selling, reconstruction, and possibly upgrading. While building your defense up, you'll want to consider not only the usefulness of the tower (perhaps its base rating and growth rating) but also the abilities which it may learn! A tower may have bad overall stats but have a slowing ability. This allows for the concept of Towers that do not attack but instead only Cast Spells. Towers such as these may be complete support towers with abilities that increase damage output to nearby towers or even debuff enemies as they come by, dealing no damage in the process. It has actually come to the point where there is an entire race dedicated to casting spells with absolutely no regular attacking tower to build. It is recommended players not try a support race in a single player game.

One example of a new type of ability that has been created is Summoning. Towers can summon units to aid them. The amount of mana used to summon a creature determines it's overall usefulness. Summoned units are sometimes controllable, sometimes act independantly, have Autocast, and often many of their own custom abilities. The Archmage of Frost is an example of a pure summoner tower. It has only three abilities: Summon Ice Elemental, Summon Frost Drake, and Summon Shiva. We now have a tower that has no attack, but instead summons a unit (Ice Elemental) which also has no attack -- Ice Elemental can only cast more spells (Or more summons)!. At later stages of the game you may see a summon tower with many active summons working for it. The best part is that all damage done by the summons are actually treated as though coming from the summoner, providing the summoner with bonuses for kills and damage done.

Independent Games

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In Experience TD, you may currently select up to five different game types: Classic 2P, Classic 3P, Classic 4P, Classic 8P, and Free For All. While the names are slightly misleading, all game modes support any number of players and will balance accordingly. If you choose Classic 2P, there will be only two enemy spawns, and two paths, but they will gain more hitpoints and speed for each additional person beyond the second. Depending on what mode you choose, you play on different areas of the map. There is an area for each mode. Free For All is an extremely special case. When choosing Free For All, every player in the game now runs an independent thread to control their game. This means that all players can choose their own difficulty, game speed, terrain scheme, and Pathing Setup.

If playing independently in a Free For All (not waiting for slow people, etc) wasn't good enough for you, each player's game will restart upon victory/defeat. Anotherwords, If you beat Experience TD, you can stay in the game and play another round on a different difficulty, game speed, terrain scheme, and pathing route without restarting the map! If you are playing in a Cooperative game (Classic), the first player (usually host) will be able to restart the game and even choose a different game type (e.g. You may try Classic 4P with 8 players, lose, then choose for everyone to play in a FFA).

Multiple Pathing Maps

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In the Free For All game mode, each player is given a section of the map to play on, void of any pathing. Instead of playing on an already existing path every single game, players can actually choose from a selection of pathing routes the enemy creeps will follow. Routes range from a single strait line (from spawn point to leak point) to a series of loops and turns to a series of T junctions (where enemies split into two smaller waves) and teleporters. After selecting a pathing route, the map automatically generates all the terrain Dynamically, sets pathability and buildablity of the tiles, and even modifies the difficulty in relation to the game speed. What this means is that at insane speeds (A new wave spawns every couple of seconds) you may be getting double or triple waves due to loops and turns, so the difficulty shouldn't scale up as high. The same pathing route selected at Per Round speed (A new wave spawns only when all enemies have leaked or have been killed) would be scaled to be drastically more difficult due to the turns and loops providing much better terrain to build on. In some cases, the difficulty is raised by 2 or 3 times normal. Upon victory or defeat, the player is then given a chance to select a new pathing route.

Dynamic Terrain

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The terrain you play on can be picked from multiple schemes. You may play on a generic Village - Fall tileset with short grass, rocks, and cobblestone, or you may pick from another set of tiles such as the Sunken Ruins tileset with sand and bricks. Other tilesets exist as well but may need to be unlocked... This feature adds no practical value to the map, it only exists to change the feel of the map if you find replayablity in it.

Beyond just picking a tileset to play on, there exists towers which actually terraform the map. One of the towers from the Ice race actually makes it snow and converts the terrain around it into snow and ice (Snow for buildable areas, ice for unbuildable creep paths). This feature adds no practical value to the map, it only exists to make one say "Oh thats cool".

Autocast

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In a tower defense, chances are a player will have massive amounts of towers (20, 30, 50, who knows). Experience TD offers towers to have active abilities to be used. In order to keep the game balanced the towers are given the ability to autocast their abilities. Now instead of making a simple trigger which just attempts to cast spells randomly, A very complex system was created to help aid in the choosing of what spell to cast, when to cast it, what to cast it on, etc. Many abilities have specific targets that are better suited than others. The following are some examples of how autocast actually chooses.

Debuffing Abilities: Abilities that debuff an enemy (such as slows, armor reduction, non-stacking damage over time abilities) always focus on more powerful units first. They also favor units that do not already have their specific debuff at the time. So a tower with a stun ability will try to stun the biggest baddest enemy in the area, but will not choose that enemy if it is already stunned. The interesting part of this is that Autocast treats passive orb effects (such as poisoned attacks, frost arrows, corruption) as spells which are activated by attacking! This in effect forces towers that these orb effects to choose different enemies with each attack; specifically enemies that aren't suffering from their orb effect at the time. In the case where the debuff exists on all potential targets, a target is then chosen randomly. Poison towers that deal very little damage but instead deal damage each second after the attack generally do not work well in TD's because the DPS effect occurs only once and doesn't stack. The Autocast System forcing them to choose different units each time they attack maximizes potential DPS for the tower by spreading their debuffs across multiple enemies. In many other Tower Defense Maps, players would often group all their poison towers into a hotkey and force them to "stop" every second in order for them to attack different targets, but in Experience TD this is done for you.

Buffing Abilities: These act similar to Debuffing abilities except they prioritize higher valued towers. You may see a Tower with an Inner Fire ability (increases damage) casting Inner Fire on all of your best towers, but ignoring the crappy cheap towers that don't benefit from it as much. Other buffing abilities such as those similar to roar (area of effect damage bonus) are casted when enemies are coming near. Generally the Autocast system picks the ideal time to use the abilities.

Area of Effect Abilities: A simple process, pick the area with the highest concentration of enemies and cast. In the case of the Area of Effect being centered on the tower (e.g. War Stomp or Thunderclap type abilities), the tower will only cast when a certain threshold (number of enemies in the area) is reached. This prevents the tower from activating the ability when only one unit is in range, which is often the case when a wave of enemy creeps is drawing near.

Sacrifice Abilities: Some towers can sacrifice other units it owns (such as summoned units) for a temporary buff or maybe just free mana. These towers will automatically sacrifice the units only when needed.

Silence Abilities: A silence ability generally chooses to silence an enemy or group of enemies which contain a high mana value or large concentration of units with alot of mana.

Custom Abilities: Certain custom abilities which have very obnoxious requirements or effects may have specially designed condiitons for the spell to be cast. Each ability can have its own conditions to be met to maximize the usefulness of even the most complicated spells.

Unique Tower Concepts

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There are quite a few towers in Experience TD whose concept has never been seen in any other map. Here are some examples.

Capacitor Towers: For these to work, you must build two capacitor towers. Each capacitor tower has a polarity: Positive or Negative. Every capacitor tower seeks out the closest capacitor tower (in a certain maximum range) with the opposite polarity and creates an electric field between the two towers. Any unit passing through this electric field takes damage (for the sake of simplicity, each capacitor tower deals its own damage to the unit). The towers have no attack, only the field between two capacitor towers deals damage. The towers always seek out the closest tower with opposite polarity. If the tower it seeks out is already generating a field to another tower, it may or may not disrupt that field depending on who is closer. This limits the placement of capacitor towers but also allows for interesting ways to get the best setup (building over a four-way junction on a diagonal for example).

Chain Lightning Towers: Every so often the Chain Lightning Tower attempts to find the closest enemy in its range and shoots lightning at them. A single chain lightning tower alone is nothing special, that is why there are repeater towers. A chain lightning tower can actually arc lightning through friendly repeater towers to enemies normally outside their range. This of course is not limited to just one repeater tower. A chain lightning tower can invest points to increase permittivity thus allowing the tower to arc lightning to up to 5 repeater towers! When I first created chain lightning towers I put no limit to the number of times it can arc, and quickly put a cap on it as I built a large cluster of chain lightning towers and about 30 repeater towers in a row to encompass the entire map. Since repeater towers have no function at all other than to extend the range of chain lightning towers, they then have the conductance ability (improves as the repeater tower gains level), which modifies the damage of the lightning being arced through it. Low level repeater towers reduce the damage by up to 60%, but as they gain levels this rapidly decreases. If one is patient enough to get a very high level repeater tower, they may even see lightning gain damage as it arcs through. If this wasn't cool enough I decided to make the lightning builder a conductor as well, so chain lightning towers can always arc a bolt through a lightning builder.

Charge Tower: This tower acts as damage and support. It's main attack deals minimal damage (1 to be precise), but it has a stacking damage over time effect on each attack. So hitting the enemy once deals 60 dps for 10 seconds. Hitting the enemy again and it becomes 120 dps, then 180, 240, etc (These values also increase as the tower gains levels). The charge tower also can learn the Supercharge ability. This tower buffs nearby towers and itself with a supercharged attack. The tower gains massive bonus damage (up to 11x damage) for its next attack. If the tower casts a spell instead of attacking while being supercharged it is automatically multi-casted up to seven times. How does this work? Well, whatever ability the tower casted is simply casted 6 more times on random units/points in the vicinity of the target (at no mana cost). In the case that the charge tower has a supercharged attack, it will deal the current DPS that is occuring on that target, times 10, to that unit and units adjacent to it. Obviously the synergy of this supercharge with other towers (such as those with big critical strikes) makes it extremely valuable. Thunder towers can deal a 6x critical, but when supercharged (11x damage) this becomes a 66x critical strike. Not bad.

Firehound Tower: This tower is nothing more than a post on the ground. But attached to that post is a magical leash, and attached to that leash is a fire hound. Consider it a 'pet'. The fire hound inherits all abilities of the Tower controlling it, and benefits from all new abilities learned. The firehound roams the area (which it's leash allows) and attacks any ground units it finds. The damage done and kills provides benefits to the tower controlling the fire hound. This same ability was then given to the fire builder. So when you choose the fire builder, it comes fully equipped with a baby firehound (not as powerful as the firehound tower's firehound) on a leash. One critical drawback of the Firehound Tower is that it does not transfer items to its pet, so it is unable to utilize an important aspect of Experience TD.

Siege Tower: The siege tower by itself is nothing special, but one of its abilities it can learn (Aerial Support) is a new concept. The ability does nothing for the siege tower, but instead creates multiple gryocopters (air support) which roam the sky above the siege tower and attack anything that it finds. Every point spent in Aerial Support creates another gyrocopter, so you may see alot of these little things flying around. The gyrocopters act independantly and are not selectable. The damage done and kills provides benefits to the tower controlling the gyropopters (Siege tower). Each gyrocopter has machine guns (anti ground) and missile launchers (anti air) with unlimited ammo. The Aerial Support ability is a what i refer to as a "pack ability" (control a pack of units"). The gryocopters are pretty much permanent summons.

Items on Towers: Towers can have items, or just use them (This isn't new). You may stumble upon a book of magic while playing Experience TD. When a tower uses the book of magic it immediately gains access to learn a new ability. The book of magic will have a mana requirement to be used, so putting a very powerful spell on a cheap arrow tower won't be possible. Similarly, the book of magic may have such a high mana cost that only select few towers can even use the book (Probably ones from the magic race). Other items may include active summons, bonus damage or attack speed, or bonus experience rates. Some towers may be able to convert items into other things (alchemy, items to gold).

Detailed Statistics

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Players have access to see statistics of various things occuring in Experience TD. Any player can view stats on how the towers of any other player (or their own) are doing. The stats are on a per-tower-type basis. These stats include: Number of towers, kills by towers, damage of towers, and damage per round of towers (if game speed is per round). A player can also view general stats of all players which include total kills, current amount of gold and research, damage per second, and damage per round. The players can also view statistics of the current and next round of enemies. These statistics include the unit types which will be in the wave, their respective count, hit points, mana, damage done when leaked, bounty, armor, evasion, damage reduction, spell resistance, movement speed, mana regeneration and life regeneration. Also included in the enemy stats is the total bounty received from killing the entire wave as well as the completion bonus when the wave is completely destroyed or leaked.

Custom Bounty

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Experience TD features a custom bounty system. Based on what difficulty the players choose you may get more or less than the default bounty. Bounty is independent in free for all games (meaning each player gets his/her own gold bounty when they kill a unit) and shared in a cooperative game (meaning bounty is equally distributed to all players in the game). In Cooperative Tower Defense maps without shared bounty you tend to see one player getting overly stacked (which makes it hard to balance since they can buy more of the best towers), so shared bounty gives all players equal ground. Not only does shared bounty prevent players being overly stacked but it also promotes teamplay aspects of building towers in other player's areas. In a cooperative game it shouldn't be uncommon to see someone choose the Ice race (very orientated on slowing enemies) and build everywhere, or someone to choose the Darkness/Light race (orientated on debuffing and buffing respectively) and build in other player's areas. The goal of cooperative TD is to win, not to simply hope that the other players don't leak and have to worry about them complaining of you stealing their gold. When shared bounty is active, the players will see the bounty value upon killing a creep as well as a signal to specify which player did the killing (colored brackets around the value).

Items, Recipes, and Combos

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There are a number of ways to obtain items in Experience TD. Almost every enemy killed has a chance to drop an item (sometimes unique). Certain towers can obtain items through their abilities (Stealing items, creating items, or morphing items into other items). You can also buy items and recipes from neutral shops using research points obtained from research towers. There are also secret items (for instance, stealing from a certain enemy on a certain level) that are possibly obtained by one race yet only usable to another (stealing a book of magic only usable by highest quality magic towers). There are many different types of items you can find, which are not limited to the following.

Books: Items that are used once by a tower which allow it to learn and upgrade new abilities.

Recipes: Items that give information on what items combine into what. Recipes themselves are not always required in the creation of the item the recipe gives information on. They simply tell you what the combination is.

Materials: Items that have no use other than to fill recipes.

Weapons: Items that increase damage, attack speed, or give passive abilities like critical strike, stun, or orb effects.

Power Ups: One time effects that when picked up provide temporary bonuses such as accelerated experience rates, additional mana regeneration, or even reset the cooldown of the tower's abilities.

Legendary Items: Items that can only exist once in a game (independent in free for all mode). Generally these items have extremely powerful effects such as giving a chance to instantly kill an enemy or providing a powerful aura. They can be made via a recipe which includes at least one unique item (thus making the combined item unique) or by being unlocked.

Epic Items: Similar to Legendary items, these items have powerful effects but aren't limited to one per game.

Unlockables

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Unlockables are controlled via a personal achievement code. At any time during the game you can enter a personal achievement code (e.g. -load A8dXu3vw9) which will unlock everything that was unlocked in the previous game (which gave you your new personal achievement code). The code is encrypted with the player's name, so you and only you can use your code. If another player tries to use the same code as you, it will not work. The codes will only unlock content in the game, they will not relock content.

To give Experience TD a little bit more replay value you can unlock features in the game in a number of ways. The most common method of unlocking is to find item recipes. Upon completing a new recipe (by sheer chance or by following a recipe that was found) you will "unlock" it. The recipe will then be viewable in the neutral shops on the map. When unlocking a recipe, you unlock it for you and only you! Although other players can now see the recipe in the current game, they will not see it the next time they play an Experience TD game and enter their code. If you enter your code and unlock recipes, any player can then see those recipes in the neutral shops for that game.

Other unlockable features include secret levels, additional terrain schemes and additional pathing maps. These are usually unlocked by completing Experience TD on different difficulties or game speeds. In some rare cases it is possible to unlock permanent bonuses to all towers. For instance, by beating Classic 8P on hard mode with 8 players, all players may gain a 10% experience rate on all towers in all subsequent games they enter their code in. This feature is very RPG orientated but should help dedicated players beat Experience TD on Impossible difficulty.

Active and Diverse Creeps

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In order to really enjoy a Tower Defense it has to be challenging. Although some TDs manage to pull of a great map with the most simple type of enemy wave (One single enemy with no special abilities), it is not the style I chose to follow. Every level you are facing something different. Every level you are facing variety. There may be two, three, four, or maybe more types of units meshed together in the wave. Each unit has its owns stats. Some units may have high armor and damage reduction but no spell resistance. Other units may have high spell resistance and evasion but no armor. Often is the case that units in the enemy creep waves are active, using abilities to try and get past you. Of course when I designed the Autocast System I didn't intend it to be only beneficial to the player! One of the major aspects of Experience TD is to find ways to get around enemy abilities, whether it be silence, mana burn, or just plain brute force. When a group of bad guys decide they want to walk down the path of hell through your towers, they should plan it out, grab a healer or two, and form a well rounded team. To beat Experience TD, you should expect a challenge of an active and diverse creep wave, designed to test your creation.

Blinking Creeps

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Thanks to a great pathing system and the Autocast System, creeps can blink with amazing results. It is rare that units will blink in Experience TD and it is rare for a reason. Units will search down the path they will follow (from their location to point of leaking), find the location where blinking yields the farthest distance, pathingwise, and attempt to blink. Creeps can skip waypoints entirely, and in some cases catch up to or pass up waves of previous levels (when playing on fast game speeds). When playing on a map with alot of turns and junctions, beware that although a junction is a great place to build to maximimize tower efficiency, its also a great place to blink to minimize tower efficiency. Special care was taken to make sure the range of each blinking ability didnt go so far as to jump lanes so to speak (at least, not normal blinking units). This should provide a great challenge to the game. The best part is its all dynamic, and I didnt have to specify any regions or locations where blinking should be done. Now thats what I call smart creeps!