It's a remix of this: https://www.youtube.com/watch?v=JbXVNKtmWnc

Using a soundfont that contains the instruments from this (not necessarily the song, but the entire OST in general): https://www.youtube.com/watch?v=-iENbJFT9qU

Most soundfonts (like the ones for Mega Man X and Final Fantasy 7) are usually really clear, but I think the composer for R/S/E compressed the instruments too much, so they have a really murky sound. But whatevs, I actually really like hearing this song in R/S/E style myself.