Possible Hack

[AhmedSa-mir]

The action should only be applied when the head of the player is at the end of the block depending on the direction of the player the end of the block.
Here we apply the action if the player is at the end of the block or at the beginning of another one.

position % block_size shouldn't be used.

https://github.com/AhmedSa-mir/Paper.io/blob/506dc9f8b43c3ce0bb049ade07fd833414b83a94/gamemechanics.js#L82-L83