What game engine do I choose ?

This question has probably been asked already, but I wan't to make a fangame and don't know what to work on. I care about performance the most.

I have played a few fangames myself and I think like it's not simple to have a game than runs smoothly on most pcs.

I've made a quick research and found out about Essentials, a mod for RpgMaker XP (which this reddit seems related to), and also something called Pokemon Studio.

So yeah, what's the best engine to use for making a pc pokemon fangame ? I'm very new to all this, thanks for all the answers in advance.