Some small tunnels are too dark for my taste, I can't see my way there, also my monitor isn't the best concerning brightness.
EDIT: Played this map now with less sun coming into my flat, then it's fairly good playable...
If you jump from one of the dark tunnels on top of the first stone rocks the textures of this rock disappears, perhaps it is fixable.
Coronas need some scaling in some spots
The map overall is a bit bland, and needs some spice.
Item and weapon placement seems to be pretty random.
I would spice things up by adding some dynamic things, such as lifts, or moving parts of some sort that interact with the game play adding to tactics. You can time things so players have to interact with that instead of just running around shooting.
You can also use item and weapon placement for that or combine the two, placing powerful items in difficult spots, or exactly the opposite to create a hot spot of action, with little to none health items forcing tactics. Trick is to balance this out to make it interesting where you basically divide the players up in groups forcing tactics instead of just running around with the nearest gun you find..
example is the 'guns high, health low' rule (which i just made up ) where you place the weapons on higher levels and the health on lower levels, making seeking for health risky but necessary, forcing tactics, because the player on the higher level is 'guarding' the weapons dominating the lower player which is not dying of because he is regenerating health. You understand that by placing one weapon in the lower levels it will engage game play..
finding that sweet spot is probably setting great maps apart from average maps, and where you will put the most work in creating a map imo.
probably also the hardest part in map creating, imo..