I gave it a brief Q2'ers browse around, and I have to say it's The Pits all over ;]
There's a few things that I'm unhappy with atm (apart from some missing textures, mainly lights):
1.
As illustrated above, the floor of the hallway behind the window seems a bit thin. Undoubtedly this is the same in the original q2 map, but it kind of looks bad to me. I don't mean the floor should be lowered, but the ceiling with the lights could be, so it would look a bit more sturdy.
2.
Also, this hallway is WAY too small for proper combat. it's hard enough to squeeze through, let alone when it's raining rockets or grenades.. wouldn't like to be in there, in any case ;]
3.
Just something that occured to me when I was getting the armor. A lot of classes have more speed & jump farther than you could in ye olde q2. Perhaps it wouldn't hurt to extend this area, so it's a bit harder to jump, and forces a somewhat longer wait, like you needed in quake 2. Just my 2cts on this one :]
4.
And last, but certainly not least, I am very much against using a jumppad as a replacement for the elevator that goes up from the red armor room. An important part of q2 gameplay consisted of jumping down (which in itself is harder to do with the risk of getting propelled up by the pad), and hopping off the elevator before it took you up, insodoing blocking the way of anyone on your tail. An elevator allows for quicker & more enjoyable gameplay in that area, imo.
There are some more hallways that are a bit cramped, mainly in the grenade launcher + megahealth area, but nothing too bad. If possible, a bit more room down there wouldn't hurt, though.
Other changes in the design/layout look good to me.