EDIT: Humble Bundle for NEOGEO games include many of the games listed, please check them out first Saw this from AppSales Applications in sale: METAL SLUG 2 METAL SLUG METAL SLUG X METAL SLUG …
Metal Slug - https://play.google.com/store/apps/details?id=com.dotemu.neogeo.mslug&feature=more_from_developer
Loved this game as a kid ... still love the game now. Unfortuntaly, limited to 5 continues, so you gotta bring your A-game if you want to clock it.