There are four main obstacles in the game. Stone Walls that Bots can break down, it breaks faster the more Bots work on it. Stone Blocks, which can be pushed by six Bots and acts as the main gating mechanic. Water, which the player can move freely in but the Bots move slowly and get destroyed after a delay. And finally, Poison, which slows down the player until he faints but the Bots are unaffected. In the prototype, the Stone Block had a big number on it to indicate how many Bots were needed, but I thought that felt a bit crude. So I instead put "socket" decals to communicate how many were needed, which turned out pretty nice.