Bastion is one of the best games of the year. A single play through is probably only a few hours at max, but it is a very well done few hours. Plenty of surprises (usually more "bad guys"!) and great narration.

A "casual" and silly tower defense game where the attackers can eat your towers (and, if you aren't careful, your BRAINS!!!!!). Besides the normal sequence of levels, there are multiple alternate play types, such as walnut bowling and a puzzle mode where you place the attacking zombies.

Fight, "sing", and collect things through your travels as your explore your underwater environment. For the harder parts, you can use your collected food items to give yourself a boost and healing. As you progress, you gain access to other "forms", which give a few more useful abilities (hint: you can switch forms using the number keys; you don't have to sing them (this especially becomes useful during some fights which require quick changing)). For the most part, I liked the background music and thought it made sense for your current area.