Alien Syndrome on the Sega Master System is a port of SEGA’s 1987 arcade shooter, and it’s got that classic top-down chaos where you blast through waves of creepy aliens. The two-player co-op is where it really shines—grabbing a buddy and mowing down mutants together feels way better than going solo. The levels are tight, the enemies come at you fast, and the weapons are satisfyingly chunky. Just don’t expect deep strategy—this is pure, old-school run-and-gun action with a side of sci-fi weirdness.

It’s not the prettiest version out there, but if you’re into retro co-op shooters, this one’s a solid time capsule.