The containment well of the game has quite a few hidden levels. Unlocking these hidden levels can get you more rewards, so it's quite necessary to explore them. So, below, I will tell you how to unlock the hidden levels in the Cold Zone of the Seven Day World. If you still don't know how to successfully pass through, then you must closely follow my steps. The following will introduce the hidden levels of the Cold Zone and share the strategy for passing through with everyone.

Currently, the Cold Zone containment well of the game does not have any hidden levels; it is actually a very standard dungeon area. Players can challenge it by following the set route and corresponding strategies. During the process of clearing the Cold Zone, the main technique for passing through is the reasonable use of some cover and maintaining distance, and also, one must be familiar with the route.
After entering the dungeon, players should jump off the platform and move forward. After seeing the artificial hill, deal with the sniper first, then ignore the soldiers here and continue moving forward. After going up the stairs, deal with the sniper again, and then you can see a blue supply box on the table in the middle, which contains the card for the door of the first level.

After getting the card, do not linger, directly open the door to enter the next level. After opening the door, there is a mine tunnel. Here, we can skip the small monsters on the side and directly fly down from the waterfall. Seeing the piano means you have reached the entrance of the second level. In this room, the player needs to clear all the soldiers, after which the door to the northwest on the mini-map will automatically open. Continuing inside, on the left is a supply room where there is an equipment box to pick up, and on the right is a door leading to a laser trap. After entering the room on the right, there are two choices: go left to fight the boss or go right to find a weapon box. Additionally, the boss mechanism is simple. In normal mode, we need to destroy two generators, while in hard mode, three generators need to be destroyed. It is recommended to prioritize destroying the generators before dealing damage.

The first generator is located on the second staircase to the right after entering. Before going up the stairs, remember to take an ice spike to break the ice wall of the generator, then go downstairs. On the mini-map, the second ice wall is directly to the west, but in normal difficulty, this area is empty. Finally, the ice wall to the south on the mini-map, which is easier to break on the first floor, without needing to go upstairs.

The above is the guide on how to unlock the hidden levels in the Cold Zone of the Seven Day World provided by the editor. Currently, this containment well does not have any hidden levels, and the difficulty of the regular levels is not very high. You can appropriately challenge higher difficulties, and the process is not too long.