After taking feedback from previous generic builds, City of Steam's dev team revamped the skill tree's visuals and mechanics to entice a "whoa!" out of its players. The concept is that the tree is now a maze of pipes, boilers, and valves. Players will build up "pressure" over time, pressure that can be vented into different pipes. The more pressure in a pipe, the higher a skill goes, and once a skill hits 100% pressure, it's usable by the player.
Winking says that players have more options than just filling up a pipe; they can also over-pressurize pipes to achieve higher skill ranks and take multiple paths to achieve better skills. There's even a mystery skill that Winking says will "make your character explode into pieces of bread with cat's heads stuck through them." Of course, he then says he's probably teasing about the last thing.