Well, yes. It's called the REName command (from the DOS prompt), or simply rename the file using the Windows Explorer (or File Manager if you're still stuck with Windows 3.x) to have a ".MID" extension. Now play it with any MIDI player. Voila!

The only thing special about the SFF (.STY) file format from a typical Type 0 Simple MIDI Format (SMF, .MID) file is that the SFF contains Markers (an SMF-standard meta-event) that label where the Intros, Endings, Fills, Mains, etc. are, plus a couple at the beginning that tells the destination device that it is an SFF file and what version of SFF it is. You can view and edit these Markers in most modern MIDI sequencing programs, including the $30 Power Tracks Pro Audio 6.0 or later from PG Music.

The MIDI channels have specific assignments in SFF .STY files also.