Real old school, Great shooter!
Graphics are cute, old school. Sounds are old school and right on.
This game has 4 playable characters from past games: Eri, Fio, Marco and Tarma. It has 5 stages with multiple branching crossroads. 10 Metal Slug vehicles. Bonus missions available on this version for the XBox.
The only drawback is if you die or rather when you do and run out of lives you will have to start all over at the level you're on. That SUCKS!!!!
It gets harder as the stages progress and it's not Ninja Gaiden hard but, it's hard.
If you put it on easy you will get through but, to play it real old school, leave the difficulty alone and go for it!