When i spawned the first time and looked at the gap between the boxes in front of me i though: "Ouh no, crouching all the time." Just a few second later i was nearly enthusiastic. No need to crouch, you just found the optimal height for the boxes, where the game makes the player duck automatically. So we already found something that separates your gg level from others, in a positive way! Because the level is made for quick GunGame-Action, i do not talk about atmosphere or ambienece. There are no sounds or special effects and they are not needed because they will not get mutch notice if 32 people try to kill as fast as possible. So let me get directly to the Gameplay which is most important on maps like this, refering to a concrete gamemode.
As i mentioned above, i especially like the feature with the "auto-crouch". This allows players to move quick and without getting blocked by something through the map. Only negative aspect about this: the head of the player models is always a little covered by the box above it. Furthermore if you try to crouch while in "auto-crouch"-mode under a crate, your model first laggs a few centimeters up before in really ducks, you may know this from ducking in CS 1.6. This makes it a bit harder to, for example, give Oneshots. Anyways, there are always two sides of a medal an in your map i prefer the "auto-crouch" instead of full crouching or completly free running.
The two different floors also improve the variability of situations while playing and the huge amount of crates assures that there is always enough cover. Well done so far. As an critical point let me mention the overall-size of your map. 32 players will fill the whole middle! Even if it is improbable that all players run to the middle at the same time, but also with an 8on8 it gets very diffusing. Here i would recommend to remove one crate on every side, just to disentangle that middle-chaos and prevent prefire/preaim. Except this point you created a good and flowing gameplay without any really annoying issues. Fits optimal to the GunGame-Mode!
As there is not mutch to say about other things than gameplay, i end up here and will give you 9/10 for this map. Keep up the nice work!