Chester is a 2D platformer with over 10 unlockable characters, a light RPG element and leveling up system, loads of unlockables, around 50 levels, and 8 "styles" that allow the player to change the look of the game at will. These styles include sketchbook, 8-bit, LCD, blueprints, and many more. They also each give a unique gameplay bonus to the player. The game also includes 4 difficulty levels so that almost anyone can beat the game or get a very challenging experience out of it.
Wonderful game. The art style, play style, and humor feels indie; great indie. The in-game style changing mechanic is a unique aspect and is more than just for aesthetics, which makes it even more fun.
Try the demo. You'll fall in love.