EssenceTD is a Tower Defense 2D game developed using Godot.
Like other Tower Defenses the main principle is to prevent monsters from reaching your base.
It is partly inspired from Gem craft series.

The map tiles are what constitute a map, they are divided in 4 category: Base tile, path tile, constructible tile and non constructible tiles.
The Base tile is what must be protected, it's always linked to at least one path tile.
Paths are where monsters can walk.
Constructible tiles are where buildings can be constructed. Simple as that.

• base : not constructible
• grass : impassible
• water : not constructible, impassible
• path : walls and traps can be constructed

The main view of the game is filled with the Map. It's a 2D tiled map and the camera is set to look at it from above.
When a map is loaded, paths between entry points and the base are computed and remembered.

Monsters are the enemies, they come in waves and have different characteristics from one wave to another.

• type : monster type, change appearance and base characteristics
• damage : damage dealt to the base when reached
• movement_speed : how much pixel the monster travels per second
• health_point_max : maximum amount of health point, when health point reach 0, the monster dies
• healing_speed : amount of health recovered per second
• armor_max : maximum amount of armor point, armor reduces income damage by 100 / (100+armor)
• energy_reward : the rewarded Energy when killed

• normal
• speed : increased movement speed (x1.5)
• swarm : increased monster count per wave (x2), decreased resilience (x0.75)
• tank : increased resilience and damage (x2), lowered monster count and speed (x0.5)

Waves are group of monsters. A map has a given count of wave. Each wave contains the same type of monster with the same characteristics. During a game, waves gets gradually tougher.
When a wave is "started", it'll step by step spawn monsters. When all monsters are spawned the wave is "completed". When all monsters are killed the wave is "annihilated".

• monster data : the characteristics of the monsters that are contained in the wave
• monster count : count of monster in the wave
• spawn time : time between the spawn of two monsters of the wave

Buildings are the main defense structure against the monsters. Buildings can't do anything by themselves they are sockets for essences.

• Towers : cannot be built on paths, do not influence essence's characteristics
• Traps : must be built on paths, essences locked in have short range, lower damage and higher reloading speed and special power
• Walls : paths with a wall become impassible terrain for monsters, there must be a path to the base from each entry

Essences are orbs of elemental power. They have different elemental types and using them as weapon against monsters imply different types of special effects. There are 4 base elements for essences and they can be fused to make different elements. There is a total of 14 elements and as much unique special effects.
Essences can also be combined to add their special effects. For example an ice essence's attack will stun a single monster targeted, when combined with a fire essence then the attacks will stun and damage the monsters around the target.
There is a lot of different combinations.

• essence type : the elemental type of the essence
• damage : the raw damage the essence deals per hit
• reload_time : the number of second necessary for the essence to reload and fire again
• range : the maximal fire range of the essence
• special power : how powerful will be the essence special effects
• kill_count : the amount of monsters killed
• consecutive_hit : the amount of hit on the same target
• level : the level of the essence
• behavior : the way the essence will prioritize targets

• earth : bouncing projectile special effect
• air : flat armor reduction special effect
• water : beam special effect
• fire : splash damage special effect
• ice : (water + air) stun special effect
• magma : (earth + fire) flat damage over time special effect
• lightning : (fire + air) multi hit special effect
• vapor : (fire + water) energy gathering special effect
• sand : (earth + air) vulnerability
• mud : (earth + water) slow
• darkness : (water + fire + earth) scaling damage over time special effect
• light : (air + fire + earth) scaling armor reduction special effect
• life : (water + air + earth) growing stats on focus special effect
• death : (water + fire + air) growing stats on kill special effect

• splash : hits inflict damage and effects on monsters at max special_power distance around the hit
• bouncing : hits bounce on ceil(0.1*special_power) nearby units
• flat armor reduction : reduce armor for 0.01*special_power per hit
• Beam : reload_time decreased (1+0.01*special_power) times
• multi hit : frac(special_power)/trunc(0.01special_power+1) + 1-(1/ trunc(0.01special_power+1) ) chance of dealing trunc(0.01*special_power+1) the essence's damage
• flat DOT : inflicts special_power*damage in 3 second
• stun : frac(0.01special_power)/trunc(0.01special_power+1) + 1-(1/ trunc(0.01special_power+1) ) chance of stun for trunc(0.01special_power+1) seconds
• energy gathering : steals special_power energy per hit
• vulnerability : Each hit sets a stack of vulnerability, every hit of other towers will break one stack and deal 0.01*special_power more damage
• slow : max slow 80%, slowed for (1 - ( 100/(100+special_power) )*0.8, add on hit, duration is 3 second
• growing stats on focus : increases damage for 1+(0.01*special_power) per hit on the same target
• growing stats on kill : increases damage definitively for 1+(0.001*special_power) per kill
• scaling DOT : inflicts 0.001*special_power % of the targets life in damage
• scaling armor reduction : reduces armor by 0.01*special_power % of targets armor, stackable per essence, not per hit, applies before flat armor reduction

• Closest
• Farthest
• Most armored
• Most resilient
• Least armored
• Least resilient
• Most damage
• Least damage
• Random target until it is dead
• Random target per hit
• Selected target

Fuse two essence into a new essence if fused elements can make a new one.
The new essence will have characteristics based on the average (trunc for integer characteristics) of the fused elements. The fusion will automatically level up the new essence.
Example: if former essences were level 5 and 5, the average level will be 5, and leveled up 6.
If former essences were level 2 and 5, the average level will be 3 (trunc from 3.5), and leveled up to 4.

Does the same as fusion but isn't final. Does the average of the characteristics but does not have a result level. All special effects and special power characteristics are kept.
Special power is divided by the number of the essences in proportion of their essence level.
Example: level 5 fire essence with 50 special power is combined with level 1 water essence with 10 special power. Results will have 41 (505/(5+1)) special power in fire and 1.6 (101/(5+1)) special power in water.

• Have a general destroy button, that would destroy selected tile's building or would destroy an essence if drag and droped on it
• Check Tile type before allowing building, make sure building is built before billing
• Design traps and implement
• More building designs
• Implement levels on essence
• Implement behavior on essence
• Design and implement essence fusions
• Implement ice essence and stun special effect
• Implement magma essence and flat DOT special effect
• Implement lightning essence and multi hit special effect
• Implement vapor essence and energy gathering special effect
• Implement sand essence and vulnerability special effect
• Implement mud essence and slow special effect
• Implement darkness essence and scaling DOT special effect
• Implement light essence and scaling armor reduction special effect
• Implement life essence and growing stats on focus special effect
• Implement death essence and growing stats on kill special effect
• Implement walls, WARNING walls will heavily use the pathfinding algorithm.
• Design and implement essence combination
• Limit to amount of drawn monsters and projectiles

• Info pop-up with characteristics and costs when hovering a button or selecting a map entity
• Wave progression bar or something similar (design to do)
• Start menu with map selection
• Options menu

• Everything is ugly and to be redesigned

• refactor stores to have different name/to inherit from a generic store script
• Place game logic into the game_logic global object as much as possible for easy balance tweak
• Try to get as much text resources as possible (scn->tscn)
• Utils function for map such as "find all monsters in a circle" to be put in a separate utilitary file
• Secondary class for handling energy and buying for map

• Balancing!!!
• Make smaller tiles while not changing building's size and monster size, allowing more detailed map and paths for monsters. WARNING will make pathfinding algorithm heavier.
• Make monster's move seem more natural (when they turn an edge?)
• Random module giving more random things, basically used for path choosing and monster type generation.

• Buildings could have experience or could be upgraded
• Combining essence effects could be done with specific buildings.
• Combining essence effects could be done thanks to an empty essence that will have sockets in it (upgrade to have more sockets)
• Energy pump buildings: putting an essence on a energy pump building can pump energy from the environment. For example a water tower on water tile.
• Map maker
• Player object, with saves, player crud ui, ... Experience system with extra skills and traits?
• Maximum energy? maybe have to build stockage?
• Ability to make a wave stronger, for better reward