UPDATE - Release: Cuphead, now with GOG Galaxy achievements

Careful, there's a beverage here.
UPDATE: Cuphead has just been updated and -besides the various fixes and improvements- it now has GOG Galaxy Achievements support! Time to let everyone know how all these Game Overs helped you git gud, people.
Cuphead is now available, DRM-free on GOG.com.
A quirky and colorful run & gun side scroller drawing from the wonderfully twisted cartoons of the 1930s. Go solo as the titular Cuphead or team up with the equally trigger-happy Mugman to take on devilishly gleeful bosses with your ever-growing powers.
Crazy for its tunes? Grab the OST separately.