Yeah, Cave Story is available to play in lots of places I think. Steam as well, right? I just happened to stumble on it because the OS I installed on the handheld system (ArkOS) came with some ports preinstalled, and that was one of them. Tried it on a whim.
I was scrolling through a bunch of the free PS Plus games on the PS5 and found another cool throwback game that I had no idea I owned called Enter the Gungeon. Pretty hard but a lot of fun.
Also, Tony, there are other aspect ratios on those handhelds from Anbernic. The newest one (and arguably better depending on what you're looking for) has the original Gameboy size and aspect ratio, with a bigger screen, internal wifi, and two sd card slots. But it's also missing one of the analog sticks and only has a mono speaker instead of stereo. So, pros and cons.