I'm familiar with Rise of the Triad, hwoever, it wasn't a game that EVEYONE seemed to have, like DOOM. It was very easy to get modem-to-modem games of DOOM going.
Rise of the Triad had the flamethrowers, trampolines, etc. I thought it was decent, though it's been years since I played. I played it modem-to-modem a few times.
I'm familiar with obscure FPS games, I used to try nearly any FPS in the 90's, at least once they were marked for clearance. Chasm: The Rift was quite a nice $5.00 purchase.