If you use assets you didn’t make, it’s not all original. I think already replied earlier that it’s kinda binary so if you didn’t make all, it would mean no.
Like discussion before pointed, there are lots of gray areas there. I’d personally see it better if people could just mark originality per asset type:
All original models (yes/no)
All original textures (yes/no)
All original particle (yes/no)
All original music (yes/no)
All original sound effect (yes/no)
or just even pointing out with short description how you’ve built the assets for the jam if it’s built on top of something existing (btw. this approach would fit the theme, wink wink). If assets are completely made by someone else, answer should be pretty clear.