First glimpsed over at Independent Gaming and then micro-reviewed by TIG Source's Derek Yu, Prototype 2 is a freeware shoot-'em-up you absolutely have to play. It's got fantastic graphics, sports some classic side-scrolling action and offers enough options & power-ups to remind me of the glorious Amiga days. Download it here and don't expect a walk in the park. Prototype 2 is a tough little bastard (well, either that or I'm far too old for such games and alcohol has finally started taking its toll).
Related @ Gnome's Lair: The B-Game Compo feature, Epic Saga, Soldner-X HD trailer, Platform!