I'm glad you like the game.
To make the world circular, you have to use little tricks.
When the player exceeds a limit on the left, I teleport the player to the right of the map. And conversely when the player exceeds a limit on the right, I teleport the player on the left. For the teleportation to be imperceptible to the player, the outer borders on the right and left of the map must be identical to the inner borders reversed.