It may (I am 90%, but not 100% sure of this) have been the first PC, online, FPS to feature ragdoll physics for dead players.
It employed a… rather baffling way of doing team conflicts:
You are always on Team America, and the opposing team is always Team Generic Terrorists. (With 80s/90s movie era costumes for the bad guys, dependent on map location)
What this results in is… you have your M4. You are shooting at bad guys with AK74su’s. But… from the opposing team’s POV, its the same.
So, if you kill someone… you can now pick up an AK74su. Even though from their POV they dropped an M4.
And so on, with rough equivalents as an SVD and an M110, an RPK and an M249.
These ‘picked up’ weapons would basically morph into having the ballistics of the Eastern Bloc weapon at the point they were picked up.
Very weird, I’ve never seen another game do that.
The game also had a good number of training courses, many of which were initially bugged as all hell.
I remember the SERE course failing me consistently, showing that I had been detected by guards who are apparently able to see through boulders or 30 feet of a hill (the camera would show you how you were spotted like a ‘deathcam’ and it was quite obvious it was often total bs).
Also, in certain training missions it was possible to shoot your instructor.
This would result in you being sent to the brig: Log in to your account, and for a week, all you get is a view from inside a prison cell, no game menus or options at all, rofl.
Oh, final thing: I am pretty sure this was the first online PC FPS that modelled that M203 projectiles must travel a certain distance before the explosive charge will detonate, so taking out someone with an M203 round to the face, non explosively, became a way to humiliate people, as you either had to be pretty skilled to do it , or your opponent had to have very poor situational awareness.