I picked it up yesterday after work. So far, Im about 6 missions in and its a diablo-lite game. Dungeon crawler with the turtles. Theres loot and levels, as well as skills. April stands in the lair giving you side missions. I have yet to unlock any though. Each turtle has their own specialty. Mike can tag an enemy, and while that enemy is tagged, he takes more damage. He also does better against ranged enemies. Donnie has an A.O.E that stuns enemies and is best against groups of enemies. Ralph is the bruiser who can break through boulders etc, he is also good against the bigger enemies. I forgot what leo's ability is, but he is good against enemies with shields.
So far the game is way better than I expected. graphics are OK but the gameplay is fun. its a very standard dungeon crawl. So if you're into that, and love the turtles, I'd say go for it.