Played the map last night and had some fun with it. Took about 30 minutes and I only found one secret (freezethrower).
My first observation was you seem to have a knack for use of space, in this map even in sometimes minimalistic settings you have a lot of verticality and dare I say sometimes too much to handle because there are a lot of accessible cliffs with no rewards on top and then possible fall damage, which some might find misleading or see as missed opportunities (myself I didn't mind it so much and I mostly appreciated being able to jump around on top of stuff unrestricted; but maybe you'd want to refine some of your direction there). I did find a few funny secret messages that helped make up for the occasional letdown upon reaching somewhere tricky or difficult.
Said use of space is interesting because almost in opposition to the linear nature of the level, especially after the first zone onwards (after you've escaped the first area and fought the first commander). I did notice a lot of cool loops in some sections (albeit the earliest one around the base felt experimental more so than optimized; I'm guessing this was the 'older' part of the map you had made), but that was punctuation during what otherwise felt like running through a gigantic and varied hallway with lots of height variations and fun platforming. In that sense, those (prominent) parts felt a lot like playing Jorge Brea's Quest
https://msdn.duke4.net/hotquest.php but on steroids with emphasis on action more so than on strange visuals. Normally that could be a negative but I'm a sucker for high-speed action and here as a way to literally drive the player from point A to B with no possible distraction but the occasional tantalizing cliff it worked really well and I had a lot of fun. It felt like I was following a giant LOCATOR track of my own and then that got shaken up once I reached the mines and my forward momentum suddenly got redirected into a maze, it then became a rollercoaster ride through the loops around the caves and that genuinely was pretty cool.
I also very much enjoyed the emphasis on explodable sprites being established as a common mechanic, and the tripmine set-up Aleks also mentioned. Gameplay balance i.e.. health/ammo to monster ratio I thought was good and sometimes smart with original set-ups like that one, but my favorite battle was the one against what felt like three dozens of assault captains in the final boss room.
Execution was hit or miss, not just visual but also technical. I'm guessing especially the old level parts are guilty but some are literally broken, being built out of sprites you can clip through (sometimes being used as glass or even walls, with imprecise alignment and so Duke can slip between a lot of solids), I spotted sector bugs (gate out of the first zone), softlocks (that pit in the mine doesn't actually kill you) and I'm certain have missed or could have chosen to miss entire sections of the level from skipping them altogether with the right jumping and/or crouching - the latter not being something I dislike per se, but you want that under control regardless of how loose. Some parts also have a lot of misaligned or absurdly stretched textures, not to mention sprite clipping (especially omnipresent in classic). And then every once in a while comes one specific area or scene that is not just really clean but pretty magnificent, so I wasn't sure why the level of care was inconsistent throughout as polishing the old parts to be on a comparable level shouldn't have been difficult. It's probably because you're still learning a lot about the editor and I actually appreciated your focus on the dynamic effects (I tried jumping across that one canyon to make the point to myself that I could clip through those sprites, got stuck on the tiny lip of the edge and so caught the touchplate, then the whole cave unexpectedly collapsed with me hanging off to the side and precipitated Duke to his death - that was funny).
One pigcop fell down a TROR hole into slime current, got squished inside a tiny sector there and then its innards stretched all the way up to the sky.
The loud door maze and the pigcop tank 'introduction' using an idle sprite plus pigcop next to it I thought were neat.
Somehow it gives off a Red 1 vibe to me (the original, not the remake). I'd definitely play a sequel to this, it was a good time.