1. Destroying all the lights on the hangars opens the KEK door.
2. Gaben easter egg on the computer in the alarm room
3. Gaben Radio on mountain
4. Weird tablet thing in container (What is it's purpose?)
5. Activating the alarm triggers the metrocop to move and supplies to fall from the sky.
6. The rake on the television screen in the last room on the bottom floor of the lab

If there are any others, can you give me a very small hint?

Metrocop is not an easter egg at all.
There is a bunch more.
Also,the E in KEK is a button that wont do anything before you "unlock" it

The only one I have found is the one in the bunker, when you are in the room with all the computers. When you interact with one of the computers, a very creep creature comes on the screen. Also, what is the KEK?

I found a helicopter out in the snow, dont know if its an easter egg, or if it does anything.

So, i was able to get into the Super secret Room.

Here the instructions:
1) Get to the smaller base
2) Pickup the gas can from the ground with your Phys or Gravgun
3) Throw it at the base platform from the round radio listening station: https://gyazo.com/165b95aa59ff730e456949dedfc72af2

4) Get into the KeK room
5) Press the E Button: https://gyazo.com/8df6f03412b1e0c6d0cec76c63618823
6) Enjoy the Room

It took me about an hour to solve that, props to you, Master Chief.

Whoa,i thought no one will ever solve this one.
By the way,you can use any prop you want

Oh, really? But next time save your map against decompilation :P I wouldn't have found it otherwise.. Nice gag though.
I am such a guy.. if i can't find the solution i will try anything to still get it :)

Anyone find the bunker yet, I'm having a hard time finding it

I turned off the power in the underground base and something popped up on my screen and screamed. I didn't know what it was, though. It was too fast.

Nevermind. It happens when I interact with the lemon grafitti on the wall, next to the room with the creepy dude on the computer monitor.

引用自 Mr. Spoo：

I turned off the power in the underground base and something popped up on my screen and screamed. I didn't know what it was, though. It was too fast.

Yes, but this is known already.

引用自 Megamezzomixer：

引用自 Mr. Spoo：

I turned off the power in the underground base and something popped up on my screen and screamed. I didn't know what it was, though. It was too fast.

Yes, but this is known already.

引用自 Megamezzomixer：

引用自 Mr. Spoo：

I turned off the power in the underground base and something popped up on my screen and screamed. I didn't know what it was, though. It was too fast.

Yes, but this is known already.

Oh. I wasn't aware people knew about that. Apologies

No offense :)

引用自 Megamezzomixer：

No offense :)

Is good

Go into the supply room in the not so secret bunker, and in one of the boxes has a nocollided top, next to the one with a battery and flares, hold right click with he gravity gun and you get a riders on the storm remix radio XD