Cave Story eShop and the Machine Gun Challenge?

I finished right now to port my Italian translation of Cave Story+ in the eShop version. By the way, I noticed that in the "mods" folder (the one of the challenges) there is a folder named "eggrace". That is the leftovers of the Machine Gun Challenge port. I tried to make the challenge playable by editing the "mods.txt", but when I start the challenge in-game, the tiles are all bugged. Is there a way to fix that? Someone did it? Thanks!