Level Design
The Level Design for unstable selection was very challenging due to the procedural generated levels in the game. In this case we set the rules before the map is created and there is independent rules for objects, obstacles, enemies, currency and map shape.
Map Generation
The game occurs in a cave so we used Cellular Automata to create the levels due to the organic shape that this method gives.
The first rule for the map is that there should be a freeway from the beginning to the end of each level. This way we can be sure that the player always have the chance to get to the goal.
Then we created closed regions that can be explored using different skills. The currency and the "shop" in the game is much more frequent in closed areas than in the main route, this way we encourage the player to explore.
Special Rules
Obstacle placement in the game needed a special rule that prevent them to be spawned in narrow path. This way we avoid blocking the path to the player.
Dead end regions are the most common place to find currency, this way we encourage exploring. At the same time we created a special rule for spider, spider eggs and spiderling to spawn much more frequently in dead end regions so the player will need to fight for the currency orbs.
Traversal Skills
We needed to be sure that at least one blue slime spawn near a water region because only that monster can drop the freeze water skill.
We needed to be sure that at least one turtle spawns near a pit because only that monster can drop a skill that can cross it.
We needed to be sure that at least one spider spawns inside a cliff traped region because only that monster can drop the climb skill.
Rules Tool
We created a tool that allow us to create as many rules as we need to tune and balance the map generation.