Coin Crypt

Honestly, a roguelike that will probably give me thousands of hours of playtime if I truly get the urge to complete it. It is challenging, more so than your usual roguelike, and the combination of your cards being your health and your currency makes every upgrade and item purchase such an interesting pros and cons consideration. It took me around ten hours just to beat it once on the main character, and there are so many more characters to try still. It's worth the price if you see it on sale.

A unique concept executed extremely well