Mega Man Revolution - A fan-made 8-bit-style Megaman side scrolling shooter game.

Hexen II - The Hammer of Thyrion project is a cross-platform source port effort of Raven Software's Hexen.

Megaman Origins - Between MM3 and MM4 there was a MM adventure, never told, until now:

Black Mesa - Black Mesa is a third-party remake of Half-Life developed and published by Crowbar Collective.

Hollow Knight - Descend into the Dark Venture down into a beautiful, ruined world of insects and heroes

Quake - Quake is a series of first-person shooter video games released by id Software.