There is a port of this game to the 3DS. Can I use that?

if it's not specifically a legal version, it's not legal. the only legal versions of the game currently are the Pico-8 version, its exports (web, standalone PC, etc), and the C# rewrite present in Newleste

I play it on gameboy, but I only do it for fun rather than competitive speedrunning because the port isn't legal