This game jam requires using an Unity asset pack, which makes it Unity-exclusive.

Is there a reason behind this decision?
EDIT: You can use the asset pack with other engines, as others have replied below

for anyone else reading this, You can import into godot, https://discord.com/channels/978439770747330571/1270011883944153088/127827651718...

you can still use the assets fyi - the pack comes with .fbx files for the models (as well as other formats) - they are rigged to work with mixamo as well, so you can totally use these in godot or unreal, basically any engine that can support 3d models.