I really enjoyed the map. It's well made, and I think it has the potential to be even better with a few improvements.
I was going to mention the respawn bug behind the barricade, but I noticed it's already a known issue. I spent quite a while looking for the last enemy because I thought the map had broken.
I also think the enemy waves could be a bit larger, perhaps with more enemies or higher HP. It also seemed like the difficulty doesn't change based on the number of players. I think following a *Left Life* map-style approach would work well: more players → more enemies.
Another improvement I'd like to suggest is making the map a bit more interactive. It would be fun to climb onto some buildings, get on top of cars, and explore the environment…