A portable gaming system, with a small green screen.
Upon activation, Isaac turns into a "pac-man" like creature, which gives him invincibility, the ability to damage enemies upon touch, and causing them to run away from him. This effect lasts for 5 seconds.
During the invincibility effect, Isaac's Speed is increased by 0.28, and he heals 1/2 a heart for every 2 enemies killed on use for the current room.
- The health leech effect will not work on bosses unless it deals the killing blow.
- If used on monsters spawned by bosses, it will spawn soul hearts rather than regular hearts.
- When used in the Sacrifice Room, standing on the Spikes will result in the chest being spawned with Isaac taking no damage.
- In the game's intro, one of Isaac's toys that his mother takes away appears to be this item.
- The item is likely a reference to the Nintendo Game Boy, a recognized gaming system made by Nintendo.
- Activating the item is similar to swallowing a "power pellet" in the game Pac-Man; while active, the enemies - very much like the ghosts in Pac-Man - will be colored blue and will try to flee from Isaac.
- The music that plays when activating the item is the same as when using My Little Unicorn/VII The Chariot.
- The Gamekid, like all other contact damage items, cannot inflict contact damage to Hearts or Mom's Heart/It Lives, but can do so to other enemies that don't deal contact damage to the player.
- When used in a Devil Room, the heart cost will appear darker, though this has no practical effect and is merely a graphical glitch.
- When used with Mr. Mega or Technology, once the effect of Gamekid runs out, Isaac's head will sometimes reappear to the right of him, with all of the other visual effects floating above where is head should be. Firing left will make the floating head turn right and vice versa. Does not affect gameplay, and Isaac's head will turn back to normal as soon as you enter another room or you get hit.
- Using The Gamekid while fighting Satan will cause his statue to move but will act as if the statue did not move at all.
- Will sometimes cause Isaac to shoot out of the back of his head after the effect wears off. The controls are NOT reversed, only the head is graphically reversed. Firing returns to normal after changing room or taking damage.