I picked up this bundle because I really wanted to play Costume Quest. This bundle was not much more than Costume Quest was on its own.
Costume Quest was a phenomenal game. I thoroughly enjoyed playing it. I picked up all the Steam achievements and had no qualms going back to play it again to pick up the Steam Trading Cards. I fully anticipate the upcoming sequel. My only qualm with it is that the Mac version had several game inhibiting bugs, notably in carrying over stamps and costumes from the main game to the included DLC, Grubbins on Ice. I was able to work around the issue by booting up the Windows version of the game through Crossover. Regardless, it's an issue that the developers are aware of, but have not fixed to my knowledge. Luckily, though, it won't affect most players who will be using Windows machines.
Psychonauts is a phenomenal game. Though several years old by now, it plays as well as any modern game. I can't recommend it enough.
Stacking is an intriguing game based on Russian nesting dolls. The main character stacks into other characters, thereby possessing them to complete the game. It, too, is fun and original. This game really pushes the player to think outside of the box to figure out all possible ways to complete the puzzle. I can't recommend it enough.
Picking up this bundle for just one or two of the games is a steal. All of them together is well worth the money. Replayability is high. You can't go wrong with this bundle.