Glum Buster
If you are looking for a nice little puzzle platformer to pass the time, then Glum Buster is your best bet. The game is rather odd but its oddity is what makes it interesting in the first place. The weird thing is that there's hardly any explanation or instructions given in the game. Hence, players are forced to experiment and explore the various areas surrounding them.
Glum Buster was created by Cosmind and took four years in the making using the Game Maker machine. However, it seems quite worth it. The gameplay is fun and quite enjoyable. Although it is a rather unusual platformer, it is definitely a cool game to check out.
Best of all, it's offered absolutely free. Give a try.