I'll have to say I am shocked that ROFLNauts existed without me even noticing. I have been playing Awesomenauts for about 50 hours now and didn't even know this little gem existed. ROFLNauts is a 4-player simple 8-bit beat-em up hidden away in Awesomenauts. There are two ways to get to the game. You can go to Help & Options and choose Play Tutorial. Once in the tutorial, go to the shop and buy the pixelized icon on the screen instead of the dynamite and it will launch. Or you can go to [Steam Folder] \steamapps\common\Awesomenauts\Data\Rofl and launch the .exe from there.
Ronimo Games also has been teasing what look like new skins just in time for Halloween. So far, Leon (Fencer), Lonestar (Cop), and Yuri (spaceman) have all been revealed so far. This game is a fun addiction and if you are on the fence about getting it check out my review .