Imagine a hardcore 2D physics-based action platformer (with roguelike elements) where Every. Pixel. Is. Simulated. Death is fun.
The lack of a proper tutorial and an unwieldy interface--combined with procedural generation that both hates and tries to kill you with every fiber of its code--make this a tough recommendation to the casual crowd. That said--there is a very real sense of accomplishment when you manage to survive even the starting area.
I dodged a shotgun-toting mob only to be splashed by a shattered flask of polymorph from the shelf above me, transformed into a flaming skull, and landed in a lake of highly flammable whiskey covering a bed of gunpowder. "KABOOM" doesn't quite cover it. Good times.