This video guide is in English. It is less than 5 minutes long and shows how to find all the secrets in The Alien Cube.

https://youtu.be/w6y_AGldnZQ

Secret # 1 00:18

After coming out of the starting area that you're stuck in, you'll come down a ravine and immediately find a river. Start walking parallel to the river but then make an immediate right through the field. At the end of the field you'll come to a structure containing the 1st secret.

Secret # 2 00:46

At the start of this chapter you are in a hallway at an apartment complex. Simply walk to the other end of the hallway and look on the left side of the bench to find the 2nd secret.

Secret # 3 01:06

You need to power up a generator in order to make the elevator work in this chapter. Before you leave on the elevator, you have to find gas for the generator. While searching for the gas, you're going to exit the cave system and reach an outside area. To the right is the gasoline at a campsite. However, if you make a left out of that cave, you'll find the 3rd secret.

Secret # 4 01:40

In chapter 4 you're going to obtain a lever from a dead body at one point. Once you go upstairs and use the lever to go through a gate, you'll find a tunnel on the left and then straight ahead you'll find an open doorway with a chasm that you can't cross. To the right of that chasm is the hammer. YOU MUST COLLECT THE HAMMER in order to find this secret. Later in the chapter after the ringing phone section, you'll come back to this chasm only now you'll be able to cross over it. You'll end up back in the apartment complex. Before proceeding through the door in front of you, turn around and hook a right into the room there. There's a locked chest on the floor, use the hammer to open it and find the 4th secret.

NOTE: Someone has said that the hammer is no longer in this location (see comments section of the guide). I'll update with verification as soon as I have time to test and make sure it has definitely changed.

Secret # 5 02:46

When you reach the gas station in chapter 5, simply go behind it and climb up the rubble so that you can reach the roof of the building. The 5th secret is on the roof.

Secret # 6 03:10

In chapter 6 you're going to reach a fire to the right of a bridge. Do not cross the bridge and instead hook a left. All the way at the end near the cliff edge is the 6th secret.

Secret # 7 03:40

In chapter 7 you're going to find a locked gate near a set of stairs that go down. Remember the gate. Head down the stairs and, after solving the fire puzzle, you'll come into a very dark room. On the left side of the room is a lever on the wall. Pull the lever and then run back upstairs to the gate that was previously locked. You will find it is now open. Head through the gate to collect the 7th secret.

Secret # 8 04:09

In chapter 8, immediately after taking the elevator down, you will have to cross over some beams. You need to cross the very first beam that lets you go left into the darkness (which should be the 2nd beam on the left). After walking through the darkness for a moment, you should reach a door. Open it and go inside to find the 8th and final secret of The Alien Cube!

And that's it!