there are no hoops needed to "ensure" that... its just how typescript (the language this was made in) works.... play literally any other game that looks similar
sure there are ways to fix it but its way faster and way easier just to define the size like they did here... and its for a game jam...
what a horrible choice to make a fool of yourself on the internet, while being as toxic as possible to a hobbyist game developer who put something out there to entertain people