Game crashes occasionally (most often after a new level load). However, due to the frequency of checkpoints, this rarely causes any considerable loss of progress. It felt more like a "oh well, got to sit through the developer logos on startup again" than a real annoying issue to me.

There were a few cases where the game decided to give both controller inputs to the same player at the start, but pausing the game and making player 2 leave and rejoin (by holding START) fixed this.