what EXACTLY does ultimate edition contain?

[Tuna Sandwich]

does it have gameplay changing stuff such as entirely new weapons?
or is it only cosmetics?

[ν]

Yes, you can look at the armory season pass pages to see the weapons.

Armory Season Pass 1 which includes 16 weapon bundles.
Armory Season Pass 2 which provides immediate access to all 6 new 2022 weapon bundles as they are released
... and additional standalone Add-ons including:
- Mrs. Foster Playable Character
- Cyberpunk Outfit Bundle
- Headshot FX Pack 1 & 2
- Foster Classic Bundle
- Briar’s Bobby Bundle
- Tanaka’s Biker Bundle
- DAR Assault Armor Bundle
- Commando Chicken Bundle
- Pajama Bundle
- Clot Backpack Bundle
- Dragon & Koi Complete Weapon Skin Set
- Badass Santa Bundle
- Witch Hunter Outfit Bundle
- Santa’s Helper Outfit Bundle
- Space Pirate Outfit Bundle
- Space Pirate Full Gear Bundle
- Reaper Outfit Bundle

[Tuna Sandwich]

Originally posted by ν:

Yes, you can look at the armory season pass pages to see the weapons.

Armory Season Pass 1 which includes 16 weapon bundles.
Armory Season Pass 2 which provides immediate access to all 6 new 2022 weapon bundles as they are released
... and additional standalone Add-ons including:
- Mrs. Foster Playable Character
- Cyberpunk Outfit Bundle
- Headshot FX Pack 1 & 2
- Foster Classic Bundle
- Briar’s Bobby Bundle
- Tanaka’s Biker Bundle
- DAR Assault Armor Bundle
- Commando Chicken Bundle
- Pajama Bundle
- Clot Backpack Bundle
- Dragon & Koi Complete Weapon Skin Set
- Badass Santa Bundle
- Witch Hunter Outfit Bundle
- Santa’s Helper Outfit Bundle
- Space Pirate Outfit Bundle
- Space Pirate Full Gear Bundle
- Reaper Outfit Bundle

alright thank you

[F1ReB4LL]

The Killing Floor 2 Ultimate Edition bundle also includes KF1 SDK and KF2 SDK for making custom maps.
The Ultimate Edition Upgrade DLC doesn't include them, you can only get them by buying the bundle.