Arena is a puzzle game with strong action elements. In each of the about hundred levels, the player controls a space ship in a top-down perspective and needs to arrange diamonds in a certain order. Similar to Atomix, once pushed, those diamonds keep going until they meet an obstacle like a wall or a teleporter. Some of the obstacles can be interacted with. This means the player needs to plan ahead in order to avoid getting into an unwinnable situation. However, the level can be restarted up to three times without repercussions.
The action part comes into place with various enemies which roam around the screen. It should be avoided to touch them as they can harm the player's life energy or even relocate him to a former level. These enemies can be shot with the ship's weapon, but sometimes they are required to solve the puzzle. There are also power-ups to pick up, e.g. a shield.