DO NOT BUY THIS PACKAGE! Do buy the game however! The Magicka Collection through Amazon has not had new DLC included since after September 2011. In the meantime the developer has practically doubled the total DLC for the game, and seems to be continuing (that's a good thing overall). If you are interested in this game, you are much better off finding the best value package for it. Purchase through this package and you will practically double your total cost over purchasing other, more complete packages. As you will need to activate through Steam, check there for pricing as well.
As for the game itself, which is the only source of my star score, it can be great fun but has a fair share of flaws. If you're interested in trying out novel game mechanics, the combat system can provide fairly constant novelty throughout the game. Try not to let yourself get stuck using just a single tactic or two. Be creative and the combat can end up feeling surprisingly fast and fluid. Teaming up with a partner can definitely increase the potential combat shenanigans. Steam does have a demo for the title, so you can try it for yourself a bit, but I think the demo doesn't quite live up to the full game.
Others can review this game more fully than myself, and have. I suggest you check their reviews out.