My hope was that we would get a better Doom source port that wasn't based on PrBoom. Doom64EX is an entirely unique source port specifially to run Doom 64, which would evolve into Kaiser's Kex Engine upon which the official Doom 64 re-release is made from. This ImDoom 64 is evidently just someone's fork of 64 EX.
A few years ago, I'd been playing GZDoom 64 on my Android phone with a Bluetooth controller, and it was my goto for the game, honestly. Nowadays, Doom 64: Retribution is the one to go for. Regardless, if the intent is to play it on the 3DS, it's a no-go unless we either have a better source port in general, or if someone takes the reins to port this ImDoom64 to the system. Given how well Xash3D has ported over, I don't see that being hard.