@ltspicer If you're referring to the flags summary that @Lolonois mentioned, x86 covers both 32 and 64 bit architectures. There's really no reason to choose 32bit over 64bit when a PC is involved.

ill try that, maybe it wont fritz out and go into a weird HD resolution on the old screen

@mickabrig7

I have already tried to port this natively, there is just not enough RAM to run it...
(BTW Undertale needs OpenGL, which is only compatible with the stock Raspbian image, not the RetroPie image)
You can see my failed attempt here: https://retropie.org.uk/forum/topic/2704/undertale-for-retropie-raspberry-pi