Metal Slug XX (2009)

Combat School is the attraction here, especially its Base Assault exercises built around boss encounters. Progress through the main missions to unlock the corresponding challenges, then revisit an attack pattern under different life and weapon restrictions. The PS4 release retains Combat School and includes Leona from the start; this recommendation is for that edition rather than assuming every older release includes the same extras. Start with the less restrictive exercise before testing a handgun-only variation. The detailed animation is charming, but keep your attention on incoming attacks.