Gridtrap is a single screen game where you have to move around a grid of squares to get to bombs to defuse them before a timer reaches zero for each bomb. As you move, any square you move from disappears so careful planning of a route to a bomb needs to be taken into consideration. A boot will also move around the screen that needs avoiding and skulls cannot be landed on but flags can be collected for bonus points. Rows of squares can be moved to make paths if there are no more squares to move on but skulls and flags cannot be moved off screen. If you move off the edge of the screen then you appear on the other side. If you touch the boot, land on a skull, or let a bomb explode then you lose one of three lives (four on the Amstrad CPC) and five bombs need to be defused to move to the next screen. The C64 version has a two player option with both players taking it in turns to play when the other player is killed.