Wow! Really conveys that cheesey 90ies DOS game sound. What samples have you used if not a secret?
You can find the soundfont file from pretty much any oldschool video game online as a SF2 file, which can be loaded into a sampler -- For this project, I used Plogue Technologies Sforazondo (i think i spelt that right) -- I selected the Super Castlevania IV soundfont and composed the tracks in ableton