Wow I like that version. MIDI music is so good at sounding like old video game music. I feel a deeper appreciation of the music in the game after hearing it switched to another medium.
That's because old game music IS MIDI. It'd be impossible for early games to even have music without MIDI because of the file size considerations. Even a short MP3 file exceeds the amount of disk space these games had many times over, and the audio compression technology they had then wasn't even close to the efficiency of MP3.
The MIDI file is only a direct export from TuxGuitar; It could be done WAY better with some proper software and someone willing to perfect it. For example, it's not possible in TuxGuitar to make one note sustain as others play over it without making a separate track, there's no crescendo/decrescendo/ritardando/accelerando function, etc.
It would be great if somebody could do that.