Yes, if 8088 MPH was sent back in time to 1981 it would have been possible to run it on even the very first PCs. You'd need a pretty expensive RAM upgrade (640k

Yes, if 8088 MPH was sent back in time to 1981 it would have been possible to run it on even the very first PCs. You'd need a pretty expensive RAM upgrade (640kB was a lot then - the first PCs had up to 64kB on the motherboard) a double-sided floppy drive (or flip the disk at the right point in the demo) and a time-travelled copy of DOS 2.0 or later. Making it in 1981 would have been a lot more difficult - we cross-compiled (or cross-assembled) most of it on modern hardware and the graphics conversions would have been very slow without a modern PC. Not to mention the modern tools used for composing the music and drawing the art, or how much we used the internet for research, or how we built on many years of demoscene research. But there's no theoretical reason why it couldn't have been done then.