I've seen some bonkers games in my time, notably Jet Set Willy and pretty much anything to come from the house of Minter, but I think I can honestly say Mighty Retro Zero tops them all. Steam user Kronbits (Davit Masia) has jammed together just about every 8-bit genre I can think of into one bizarre yet beautiful fest of explodey fat pixels.
While MRZ is still in development, the videos and animations so far released show gameplay based on Arkanoid, Pang, Metroid, Portal (yes Portal!) mashed up with Donkey Kong, Lode Runner and many others and a sprinkling of retro gaming references (DOTT purple tentacle for instance) and a large dose of utter madness! All contained in an 8-colour palette world which should be garish and hard on the eyes, but Davit has made it work just beautifully.
Development is going at a pace, and all the newest features are being logged on his TigSource Development log.
Davit is aiming for a release by the end of the year initially on Windows PC, Web (flash) and Ouya and hopefully Mac and Linux ports to follow and is also looking to get on Steam via greenlight. So if this is the sort of thing that gets you going, (and if you're reading this site then that's pretty likely!) then head on over and give him a YES vote.
Steam Greenlight page
TigSource Development log
Indie DB page