I have found little "black cubes" in 3 maps in this game, and am beginning to wonder if they are in every map. They have the words written upon them, "THE CASTLE was here." It has to be resembling one of the game creator's "nicknames." The three levels i have found them in chronological order on are:

1. Rise hard

2. Sandstorm

3. Secret War

1.Rise Hard

~IMPORTANT~

Put sv_cheats 1 on and play with godmode enabled

-You must be at end of level for this to work, right at the point where you bomb the pillar and bring the leader down.

-right when you set down explosive, run to the left in the corner and you will see a little black box that says that text (see above).

2.Sandstorm

I remember finding this one before, but cannot note where it is now. (very sorry, help me out if you can!)

3.Secret War.

-when you get to the point when your new objective comes up, (it says Start up main generator or something.)(it should be very near the beginning.) go through the door that the man unlocks and proceed through the next door where the generator is.

-turn it on

-go to the point afterwards (should be after the place with all the barrels that explode) and pass that up.

-there should be 4-5 enemies waiting before the part where you jump the door and go in the hole.

-kill the enemies, jump the door, kill the enemies on the other side, but dont jump in the hole!

-there should be an elevator across form the door you jumped, go there, go to the alcove to the right of it, turn around, look down, and you should see the black box with the text.