Yeah, I seem to remember Resurrection being much more difficult than Trilogy - although it was certainly the better game. If they only could have fixed the control problems in Res, and had a bit better weapon interface, it could have been great.
My main problem in Trilogy was just getting lost in the sprawling levels. A lot of them lacked the purpose of design that levels from similar games of that period (*coughcough*DOOM*coughcough*) had, and so I ended up just taking the cd out of my playstation and putting it in my CD player to listen to the excellent soundtrack.