Not the worst for a first map, but...
- Your brushwork is painful to look at. There are a lot of small bits that you can get stuck on, and they're just thorns in the eye. Try and stick to a consistent grid size.
- You didn't put a blockbullet ramp on your stairs.
- As with basically every in-dev map, there's massive Sniper sightlines everywhere currently, particularily this one:
- The one-way doors aren't marked at all, which isn't a huge issue but can be infuriating when in the heat of combat.