Well, I made it about halfway through the Wharf, but the lag is getting too bad now so I can't properly play the game

. At least not on my ancient laptop. I'll find a workaround (probably going to install this on my parents pc so I can play whenever I visit them lol) but at the moment I'm stranded.
I'll just leave some short reviews about the stuff I did play. It's obviously very well made.
City under Siege: as I said the hovering spaceship and the destruction really sell the idea of an ongoing invasion. The map feels like a throwback to the original game, but adds a lot of modern elements at the same time (scripted sequences, team mates, sense of progress etc.). Also enjoyed the shrunken parts, and the lego house.

Ammo was a bit sparse, but I managed to pull through.
The alien bit reminded me of Imperium, but this might be a coincidence since both are inspired by Unreal. Didn't really enjoy being restricted to one weapon, but it didn't overstay its welcome. The final sequence with the alien space ship was nice. It reminded me: at one point we wanted to add a similar sequence to the Imperium episode. The alien space shuttle (at the end of L4) was supposed to be flyable, but we eventually abandoned the idea.
Big Trouble in China: I remember the beta version of this map, fun romp. One of the cleanest maps Sang made. Again, the skybox and the unreachable scenery add a lot to the level. Funny how the gameplay is almost the opposite of the last one: ammo, guns and health everywhere and a contant supply of baddies. Fun map, also great subway ride at the end.
The wharf: as I said, I'm not able to finish this yet. I liked what I saw so far, especially the sushi-restaurant. Well designed and balanced gameplay.