I was an Atomic Mutant!

From the creator's website: "You are the monster!! A smashing and stomping homage to 1950's b-movie monsters. Arcade style gameplay through virtually limitless levels. Play as one of four powerful monsters: The Brain from Beyond Infinity; Reptomicus; the She-Beast; or the Invader from Dimension X. Live the movie as you play in original black and white, and unique "Canopy-Vision" cinematic mode. User summary: An arcade stop 'n' Smash game where you take one of 4 monsters and destroy every building in a level to move to the next level. Monsters are on a Godzilla scale, and all are based on 1950s movie monsters - the 50-foot woman, Godzilla, etc. Your weapons include eye beams, Stomp attacks, ray guns, etc, varying according to the monster. Opposing you are infantry, tanks, aircraft (varying from P-51 fighters to B2 bombers), etc. Powerups are sprinkled around the levels, and the game offers a variety of (mostly cosmetic) options such as playing in greyscale or 'canopy mode' (which displays the screen as though it was on a drivein movie screen. Plays in Windows 7, possibly without compatibility mode, but better in Windows XP SP3 mode.