When my attempt to convert a MIDI song into .wav makes D_RUNNIN sound better than the original

[DynamiteKaitorn]

I just wanted to convert a few DooM songs into MIDI to attempt to make a remix but I might have messed up somewhere. I tried using different programs but to no avail so I went with OpenMPT which managed to load the songs in .it format. Let's just say it may have read the files a bit oddly and resulted in an interesting result:

 

http://www.mediafire.com/file/d33utxx8ezbqj4v/DOOMRUNNIN.zip/file

 

It mostly sounds the same but there is a noticeable difference.