in the base 2.0 Factorio (2.0.15 build 80 108, Win64), the mod errors out on initial load. I do NOT have the space expansion.

Failed to load mods: holiday-artillery/data-updates.lua:94: attempt to index field 'artillery-shell-damage-1' (a nil value)
stack traceback:
holiday-artillery/data-updates.lua:94: in main chunk

Mods to be disabled:
• holiday-artillery (2.0.0)

Thanks for the report, I plain forgot to test it with Space Age disabled. Just published version 2.0.1 which should load just fine whether or not Space Age is enabled. Now you can get back out there and spread more Holiday Cheer!