One game I really want to buy is Cuphead for Steam. As a part time animation enthusiast, this game looks amazing to me. I already caught a subtle reference to the cartoon "Swing You Sinners" involving the flower boss.
It's a pretty good game. The level design feels very smart, and it encourages you to go back & 100% each stage. The extra stages for if you have 3D World save data are kind of annoying, as it takes about 5 minutes just to run through each one without collecting everything. So I was slightly disappointed. But, I would still recommend this game, and it's quite fun.