Serious Sam Siberian Mayhem: How to Unlock the “Freezer” Skin for The XPMR “Burner” Raygun (2022 Christmas Event)

The Christmas update was released yesterday (December 18, 2022) and one of its new features is the “Freezer” skin for the XPMR “Burner” Raygun. You must find one Christmas tree in each of the five story levels and decorate it with the items that are scattered in a small radius around it. This will open a portal next to the tree, which leads you to a small challenge that rewards you with a weapon part upon completion. Finding all five parts will unlock the weapon skin.

You don’t have to finish the level after collecting a weapon part and you don’t have to get all of them in one playthrough. You can immediately quit and load the next level from the menu.

The skin can be found in the “Game Options” menu:

Thanks to ExTaZzY and MaxRadishOne for helping me find the locations.
Thanks to UrbanDeHuman for confirming that you can quit the level after collecting a present.

This Christmas tree can be found at the beginning of the level.
After collecting the shotgun at the end of the beach, turn left to find the tree by the water.

Facing the hill that leads you to the next area:

Collect all the decorations and bring them to the tree to open the portal:

Defeat all the enemies in the arena to receive a present:

This contains the weapon part:

This Christmas tree is located in the “Energize” side mission at the beginning of the level. Get to the other side of the crane area and enter the area to the right.

The tree is standing to the left of the hangar:
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Press the button to turn the lucky wheel until it lands on the present symbol:

This Christmas tree can’t be missed. Shortly after finding the quad bikes, you’ll encounter the first sentry tower on a large open field.

The tree is located right next to the gate that leads you to the rest of the level:

Defeat all the enemies in the arena to receive the weapon part:

This Christmas tree is located in the same area as the Burner gun.

It’s right next to the weapon:

Find your way through the maze while collecting keys and killing Octanian Zealots. The weapon part is waiting at the end of the maze:

You’ll find this Christmas tree after walking through the train station.

Facing the building that you come out of:

Defeat all the enemies together with your armed snowman friends to receive the weapon part under the large Christmas tree in the arena:

Enjoy your new weapon skin: