I like a lot of the choices that were made with this. The game does indeed contain Xbox controller plug-and-play support. That support seems to work well everywhere, except the exiting screen (the furthest-right screen in the Tab menu).
The Xbox support is excellent, because it's specific to Xbox controllers, and is not generic. In other words, if you use a generic controller, and plug the game's keyboard/mouse defaults into JoyToKey, the game will still cooperate with the custom layout. So, yes - the game is compatible with hundreds of controllers. It's wonderful.
There were three small things that bothered me. 1) It's possible to enter the Tab menu, by clicking on the upper-left white menu. That functionality is not necessary, because you can already enter the menu, with Tab. 2) The mouse cursor is really difficult to see. I wish it was thicker, and black and white. 3) There doesn't seem to be a way to save progress.