Decent gameplay, the main reason to bother with it is for all the crazy 80's and early 90's references. There are a few internet meme's strewn throughout and it's all very welcome in my books.
The retro game references are just superb though, with an entire section dedicated to the original TMNT NES cartridge among others, it's a blast to just experience the game as a whole.
The game had a lot of love put in to it, the music is incredible and I had to download the soundtrack afterwards and I still listen to it every once in a while.
Definitely worth a sale price purchase in the 10 to 15 dollar range.
I can't say much about the controls as it basically plays like a slightly better version of the original top view GTA games (1 & 2) mixed with an 8-bit NES style. The map can get a bit convoluted and collectables are a bit annoying to find even with a guide because of the shoddy graphics but it's still do-able with some focus.
The thing is you'll either love it or hate it... and if the references can't save you because you're too young to understand it, then you should probably stay away because it's all about the references, not so much about the gameplay.