For me the gameplay is way too fast/intense for me. Like it's Quake on steroids. I used to play NS1 at a decent skill level, but my reflexes have slowed way down.. plus my computer isn't able to run NS2 at a decent frame rate. So I get mauled by Skulks, and as a Skulk I can't keep track of bunny hopping Marines either.
If there was a gameplay mod that slowed things down (and had other changes to suit the slowed down gameplay), I could have a lot more fun