Shoot 1UP is a top down shooter with a twist. Instead of finding the usual power ups and 1UPs, each 1UP collected creates another ship which is added to the player's ever-growing armada right away. Using the L and R-trigger buttons, the player can adjust the distance between the ships to either dodge bullets or unleash a combined enormous laser beam on the enemies. The more ships in the armada, the more upgraded the standard weapons become, and the higher the score for downed enemies.
The player can gather as much as 30 ships simultaneously on the screen to wreak havoc. If there is a second player, as many as 60 ships can be used at the same time!
There are 6 stages to get through as well as several difficulties and a mode which plays more like a traditional shooter, where the player has only one ship and one life. In this mode the 1UPs have been replaced with weapon upgrades, so instead of a growing fleet of ships the player gets better weapons over the course of the game.
There are 17 Awards to unlock, ranging from reaching certain score marks to finishing the different difficulties and killing enemies a certain way.