Hehe, deathmask. I remember that. Never have I seen a more unusual (read simple) 3D engine. It really wasn't more than a texturemapped "3D monstermaze", all movement was restricted to solid steps forward, backward etc. and the rotation was fixed at 90 degree increments.
The monsters reminded me of some sort of surreal Terry Gilliam animation too.
Yet despite all this, it was actually a good laugh to play, especially head to head.
"Fears" never really inspired me much - technically competent as it was. Whilst I also found breathless a bit lacklustre, it was a big step in the right direction however. For me, the biggest downer was that the environments were just too samey, no doubt inflicted by the 'square block' basis of the map. I'm sure this approach allowed fast depth sorting etc. without a BSP, which gave it speed. Combined with the 1x1 pixel display, this was a game you didn't have to squint at and scaled very well with your hardware (unless you had an 060 of course).
Gloom was good fun. It didn't really pretend to be anything more than it was: a gratuitious shoot 'em up, just in 3D. The lack of any real 3rd dimension (that is different height/level rooms, stairs and so on) changed the feel of this into a simple maze game, which coupled with the non stop violence gave it a really bizzare atmosphere.
Genetic species was different again. It had even less 3D complexity than Gloom - in addition to the lack of stairs etc. the walls were also 90 degree (like breathless). However, the designers made sure they used the speed gained from this to create some pretty cool effects and it had atmosphere.
For me personally, the only games which actually deserved the title "Doom Clone" were AB3D1 & 2. Both had, what at the time was considered to be a 'real' 3D environment, with arbitary angled walls, different height walls, floors, lifts, teleports, stairs etc. They also allowed two level rooms and deep water, something Doom didnt have. They had a tense, dark atmosphere, and TKG in particular had effects that really made it stand out. Bumpmapped sprites, what a fantastic idea!
You can tell the game was half finished, of course. The editors allow 8 view directions for monsters but in the game you only see 4 (which was a bit naff). There were also a bunch of features you can modify with the editors that never made it into the game. With levelEd, I discovered some flickering light animations (not the slow pulsating glow effect, but your knackered fluorescent tube), even animated water depths (like a tidal effect), all of which work perfectly but weren't even documented in the original editors...
