How to finish this map without cheats.
Here is the tips for hardest parts:

Starting room: - Where the first monster sit in the table there is a switch right from to the monitor.

Area with unreachable blue keyswitcher: - When you passing in the long corridor where 3 Laser Tripods spawning behind you in the exit you can find 1 pipebomb laying in the floor right side in front of front door. Pick it up and throw it through the window where 2 pig cops walking and blow up that box which is marked with nuclear sign and explosive label. After this now you can see a red button and just shoot it on and you can enter into this place.
The blue keyswitcher is opens that door which is opposite the window.

Snowy area: - After when you fought with the Assault Commander alien you can enter this place. And you can see a submarine in the ice. Go to the left side and blow up the hatch and jump down into.


I will not detail the rest. You will solve it.

in the snow

im stuck outside

So sad that it is not possible to finish it without DNCLIP and DNKEYS.

I for some reason can't leave the starting room. Had to DNCLIP though a door.