This is pretty nice for a first map – especially a seven-hour map (essentially a speedmap)! It’s no masterpiece, but quite a few experienced mappers would struggle to make something this coherent in so little time. Well done!
Some feedback, in case you’re interested:
It’s a fully functional map! All triggers seem to work properly, it’s sealed, layout and progression make sense, and it’s decently balanced. Given that your aim was to learn all the basics of mapping, I’d say this is a resounding success.
The style is pretty original, too. And it’s not just a bunch of square rooms and boxy brushes – there are some nice curved/angled shapes and broken bits.
The somewhat less good
Skill settings have not been implemented, as far as I can tell.
The secrets are a little unrewarding, as you have pointed out. But hey – there are secrets, and that’s good!
Well, to be brutally honest, it’s not the best-looking map I’ve seen (though it’s certainly not the worst, either!).
Texture choice comes across as a bit random and chaotic, and some textures could be better aligned (e.g. base textures featuring lights and tech panels tend to look better when the brushwork follows the shape suggested by the texture, and plenty of textures look better when they’re not cut off mid-pattern. But I’ve seen far worse texturing; again, for a first map and for a speedmap, this is really decent.
(To a lesser extent, the same could be said for the brushwork, but here I don’t want to be too critical – especially seeing that your brushwork is more than just a bunch of boxes, and the map is properly sealed.)
The lighting is also not bad, but could be better. Contrast and shadows are good, but this has a little too much of both. I don’t know which light tool you are using, but https://ericwa.github.io/tyrutils-ericw/ has a load of features to play around with so as to avoid the kind of pitch black swaths one sees in this map. But that does require practice.
In short: really nice debut. Please keep mapping! Given that this is where you’re starting from, I can’t wait to see what you end up making once you’re more experienced.
Also, you might want to consider posting this over at func_msgboard, in the http://www.celephais.net/board/view_thread.php?id=3&start=14608. There are lots of experienced mappers over there who can give some very sensible and valuable feedback.