yup only during the jam. I've got a few videos of me working on various bits of the art that I streamed during the jam. All the environment stuff is assets I only did the character, guitar, GUI, effects...
I'm pretty fast and I've gotten pretty good at planning over the jams I've done. I have a fairly developed pipeline for asset creation honed over many jams. Not to mention I worked on the project full time during the jam so probably around 100 hours over the 8 days.
I firmly believe half the battle when you're building projects with unity is knowing what assets you own and what they're good for.
This could turn into an extra Devon post ;D so I knew I had environment covered (the packs I used for the arenas were actually what made me want to do a jam just to use them) I just had to make the terrain itself which was pretty quick (like an hour or two) with the tools I have. I knew I had a heavy metal music pack with a bunch of different tracks so I didn't need to worry about the music. So I could spend a couple days on characters, a few days on systems and a couple days pulling the arenas and mechanics together.
All the hand drawn looking stuff (the UI, ravens, etc) were done on my iPad so I did most of that when I was taking a break from the PC, in bed before sleeping, etc. so I wasn't just hunched over a hot PC for endless hours.
there are also compromises... there's no player health for example and a lot of things that should have audio don't but the music covers that sin. I chose to spend time on adding the story elements with the ravens and the end sequence rather than flesh out those parts. So it's all give and take picking what's important.
This was the first jam I didn't pull an all nighter on (only 5am on the last day ;D ) so I know I did well.