Wow, first time i play a map like this from yours, and i admit i pretty liked it ! Very long to complete and a bit frustrating, but it's an enjoyable frustration
I like how doom style is recreated through secret areas placement (found only 5 at the first time), invisible walls/impossible jumps, enemy amount, raising platforms and puzzles. To play with original doom Midis
Just a mention: so many switches do activate things without knowing -which- ; have you considered adding cameras (though this is really not doom-ish) ?
However, i think i'll play all of your other maps of this kind