Sequence: Starting with an oddball, sequence is a quirky (some might argue that it's a bit too quirky) rhythm/fantasy/err... RPG-ish? game. You'll find yourself in something that looks like a dungeon crawler, casting spells, defending from attacks and doing some yourself... with rhythm-based mechanics. These are amazingly solid and the game's strongest point, with the visuals and the music being about good enough to keep you entertained.
Rush: Wait... this one is $1.69?!?! Buy this.
Now! If you've ever been a fan of puzzle games (and in particular of Chu Chu Rocket!), this is an absolute hair-pulling must buy. If you're familiar with Chu Chu Rocket, then this is it. In 3D environments. If I haven't blown your mind yet then it's because you have no idea what I'm talking about, as a self-respecting CCR fan should have stopped reading about 10 seconds ago and bought it. Basically, you use tiles which you can place on the ground to guide moving cubes into portals, while preventing them from falling off the stage and suffering other similar fates. Sounds easy? Hah. The visuals are great, the controls are great (which are mostly camera-related; trust me, you'll need them) and the music's pretty solid. Good amount of levels, as well, and some of the later ones can get extremely difficult.
Waves: It might just be me, but I'm an absolute fan of twin-stick shooters. With that said, until 2 days ago I didn't own one single game of the genre on Steam, and I'm glad to say I have fixed that mistake in the most awesome way possible and that's by buying Waves. Just check out the video on its store page and tell me you're not compelled to buy it with a straight face. Awesome visuals, addictive gameplay mechanics (you can slow down time?!
holy shit), perfect music and a difficulty level made to take you from beginner to hard-core all-nighter twinstick shooting raging player. I've been playing this with an old PS2 controller connected to my PC through a USB adapter, and it's finally helped me make up my mind and just go ahead and get a 360 pad.
PixelJunk Eden: This one needs no introduction. Although it's not a rhythm game per-se, the musical effort that's gone into this game really makes it shine, and the weird swinging mechanics (which might take some time to get used to) along with the weird high-contrast visuals makes this a game worth checking out. At first you might get the feeling that it's a sort of empty mechanics game, with no other purpose other than collecting shiny stuff in each stage, which you'll soon be glad to find is a pretty erroneous perception.
Anomaly: Warzone Earth: Anomaly was featured already in the Indie Bundle I, but I think it's easily among the best games featured throughout the whole sale. It's a take on the strategy/tower defense genre unlike any other, with amazing visuals (I was first introduced to this game through it's Android version which already looked fantastic, but on the PC the game's visuals are easily breathtaking), balanced gameplay, great level/mechanics progression, a cliche'd but nonetheless effective story and decent music. Definitely one of the games I've enjoyed the most in the past few months, and one I've gifted several times to friends who now have joined me in enjoying the awesomeness that is this game. Do check it out.