The roots show, it looks a lot like a Doom map. Definitely classic visuals. Though if you're not going for extreme details, you should at least make the simple(r) architecture look smooth, for instance by aligning it properly (also vertically) and using trim or flat textures (=no details, e.g. metal) on off-side faces like the insides of the windows and doors.
I think I played the map in a slightly weird fashion by not going to the water area first which made it feel a bit useless when I got there afterwards, because I didn't really need any of the items. Good, albeit occasionally indeed somewhat random secrets. Nice exploboxes (careful though: the game can crash if too many of them explode at once - no barrels'o'fun in Quake). No difficulty settings?
In-game warnings:
Mod_LoadTexinfo: 9 texture(s) missing from BSP file
walkmonster 'monster_ogre' in wall at '1712.0 -152.0 -40.0'
walkmonster 'monster_ogre_marksman' in wall at '1280.0 64.0 409.0'
walkmonster 'monster_demon1' in wall at '1536.0 64.0 401.0'
Some of the missing textures are even visible in the level - those checkerboard faces. Check QBSP's output (or log) to see the texture names in question. Those are textures that the compiler couldn't find in the specified wad file(s). This also includes textures that are used somewhere but don't actually show up because they are 'on the outside'.
Monsters in wall means they are placed too close to walls or ceilings (need to be at least 4 units away), or on a platform that's too small to fit their entire bounding box + 4 units on each side. Sometimes this can lead to monsters being stuck and unable to move.
To see warnings like this, type
developer 1 before loading the map.
A proper, "quaddicted-worthy" release follows the same standards as on idgames: ZIP file with se.bsp and se.txt, no folders.
By and large, I'd say a decent first approach to Quake mapping and with just a little more polish in some areas, it could be a good 1997 map instead of a 1996 map. Err, or whatever. Always good to see Doom people try their hands at Quake.
Demo (forgot to change the protocol, so it requires Fitzquake or Quakespasm to watch)