Imposter.IO is a melee-style multiplayer fighting game that merges elements from snake and worm games with the characters and setting of the Among Us game. An imposter is on board the spaceship. Instead of trying to find the enemy among the crew, every player assumes automatically that everyone else is out to kill them. To protect their avatar, they must kill everyone else first.
The player picks a character by color. The avatar starts with a low-level melee weapon and 1,000 lives. The player directs the character to walk around the ship in search of cubes that provide energy, health replenishment, and level-ups to prevent death from injuries. Whenever they come across another player's avatar, they make their avatar flee from it or attempt to kill it.
As with snake and worm games, the player collects cubes by directing their avatar to walk through them on the battlefield. As their character levels up, they can use the money they earn to modify the avatar's weapon, hat and color. If the player must direct their character to kill another avatar, they behead it and leave its bloody spacesuit corpse on the floor with a bone jutting out the top.
Imposter.IO also offers global leaderboard rankings, with the top 10 players featured near the top right corner.