Myriad is a side view single screen shooter where you control a spacecraft at the bottom of the screen, moving in four directions, blasting various waves of aliens that appear at the top of the screen. As you blast the aliens, they move around the screen dropping bombs on you and if you hit an alien or its bomb then you lose one of five lives. Your ship is also equipped with a limited amount of shields which protects you for a short time. There is a two player option (not on the VIC-20) and each player takes it in turns to play when the other player is killed.