Tower Defense/Shooter hybrid Sanctum is one of my favorite games of the year so far. It earned solid marks in our review, blending of two unique genres into something very enjoyable indeed. If you were thinking about checking it out, but undecided, now might be a good time: Sanctum is now priced at $9.99, which truly is a lot of bang for your bucks(s).
If you are already a rabid Sanctum fan, you'll be glad to know that the soundtrack is now available. Purchasing via Steam will run you $4.99, or you can use Bandcamp and pay what you want for it here. Now you can remember the music of those intense four-player co-op sessions while you're working out or commuting!