Striking while the iron is ice-cold, that's me.

Helltaker is an indie puzzle game about breaking into hell to collect a harem of sharply dressed demon girls. It's about as serious as that description makes it sound, but the designs are very sleek - even those that never made it into the final product. I've seen some fanart of "Generic, the Template Demon" floating around, but these three either predate her or were discarded once her aesthetic was chosen as the one to carry forward. It's interesting how elements of several of the characters from the final game are visible in each of them; Blue on the left is a sort of Modeus/Azazel hybrid, for example.

Credit to Rainbowcowdragon on Reddit for the background image.