I thought HeXen was the first FPSRPG to be released, guess I'm wrong. But if critics call this a DooM clone, they're right to some extent. But the thing is, there were few games that could could be original. It's like calling Pong a rip-off of Pong on another console because it's exactly the same sport.
But that's surprising though - how can they hate 16 players in one game? Plus a huge focus on melee, which would've been a major change to most games. I'll have to give it a try!