The start of greatness!
Supergiant's first game. One of my first PC games, and alongside Edmund McMillen's creations this game was what bought me into indie games from a young age. The game itself is spectacular. It's short and sweet and after playing the whole thing through in a session or two you will have no regrets. Even if you don't care for the story, gameplay, tunes and design will carry you through. Nothing but love.