Strip out everything inessential from the platformer, and what you get is Coal. It looks like something you'd see on an arcade machine from 1982 with a black-and-white vector graphics monitor; the music is danceable MIDI techno. Snappily response controls, double- and wall-jumps, and straightforward but nastily fiendish level design; who needs anything more?
The development time that didn't go into graphics seems to have gone into levels; there are 100 of them, and the game ships with a level editor so you can make and share your own. The basic rule on all levels is that you have to find all the keys to open the exit door; there are, however, no waypoints, so death means restarting the level, which can get frustrating at times, since some of the levels are frigging impossible unless you've got a lifetime's worth of platformer mastery. But still, tres cool.