I love this game, it combines two things I've always had a passion for, music and games. This is a space shooter that depends on the beats of your own songs. The enemies and your wepoans are either faster and stronger or slower and weaker completely dependng on the song you're playing. If you like dance / eletronic music you'll probably have a harder time playing it! I've had this on the Playstation 3 system and now own it on Steam, so it's safe to say I have around 50 hours in this.
I can only write about Beat Hazard Ultra, because I've only played that version so far. The Ultra DLC adds perks and weapons in which you can upgrade using in-game cash. Honestly, Beat Hazard must feel boring without the Ultra DLC, it breathes new life into the game, a damn good one!
Every DLC so far has not disappointed me (although there's only two o far), It just feels like a much better game if you have all the DLCs. Both will give you challenges and a ton of stuff to do. The new Shadow Operations Unit is also a great addition, introducing new ships and the ability of creating your own! Each ship will give you 3 challenges, in which some are actually pretty hard to complete! :D
Beat Hazard is the game I'll always go back to it sometime because I'll miss its craziness and how good it feels to destroy enemy spaceships. It always feels different because everytime I go back to it, my musical taste has slightly changed. This game is cheap, and if you love music I think you'll like this game too, but be sure to, at least, get hte Ultra DLC, it will be a totally different experience. Beat Hazard (Ultra + Shadow Operations DLC) is an 8.5/10 for me, considering it an indie game and how cheap you can get it, the amount of hours you'll play this will surely not be wasted. :D