Gameday Mayhem!! is Untested on macOS
Gameday Mayhem!! has not yet been tested on macOS.
About Gameday Mayhem!!
Grab a friend, hit the field, and brace yourself for Gameday Mayhem!! – the local multiplayer brawl that asks: "What if football had no strategy, no rules, and possibly… a rifle?"
It's a 3-minute duel where two players run, dodge, tackle, and fumble their way to victory. Want to pass the ball? Sure, but don’t expect your AI teammates to help—they’re barely functional.
Think Nidhogg meets American football. So, lace up, lock in, and prepare for zero strategy, all chaos.

(and Gameday Mayhem may actually be the worst game!)
GameDay Mayhem!! is 2-Player-only and local-only. It supports gamepads but it can also be played with two players on one keyboard. Try the demo to find out if your keyboard supports shared keyboard. To play online with a friend you can use Remote Play Together.
macOS Game Tests
Gameday Mayhem!! tested on macOS.
Gameday Mayhem!! is not natively supported on macOS. See below for potential ways you can play it that have been tested.
Gameday Mayhem!! hasn't been tested yet on macOS.