This is a fantastic deal and I recommend you get it if you don't have at least a couple of these games. I have not beat all these, but I have played a bit of each. Here is a quick rundown.
Deadlight- Alright game, probably the weakest of the bunch. Kind of like "Limbo" or "Shadow Complex" with zombies and annoying voice acting. But it doesn't have as creative puzzles and game play as either of those games. Still fun though.
Mark of the Ninja- This is the best of the pack I think. Its like "Shank" but stealthy. It has some great mechanics and is consistently addicting. Great little stealth game.
Toy Soldiers- It's a pretty basic tower defense but you can control what you build. Its a solid title but I haven't played too much of it.
Insanely Twisted Shadow Planet- This game is pretty awesome. Old School Metroid but your in a spaceship and you have to use all your tools to on your spaceship to progress. I like it, fun game for sure.
Iron Brigade- This is from Double-Fine, the people behind Psychonauts and Brutal Legend. It is also a tower defense and I personally like it more then Toy Soldiers. You get to control a Mech that you can customize the body, weapons, paint job, and a bunch more on.
So there you have it. I would strongly suggest getting this pack.