Hey a juice jam submission!! That was my jam 😂I played this for a LOT longer than I expected to, which is definitely a good thing.
I'd echo the below comment in saying that the controls are a little touchy, I think I'd prefer to move 50% of the distance side to side.
I actually think you could get away with keeping the slippery controls at boost speed - it felt a lot more "uncontrollable" which is definitely the vibe you should be going for at max speed!
If I had one complaint about juice/vfx, it would be that there's not enough there when you stop boosting. A change of FOV or something like that would really help there.
I don't necessarily agree that variation is required, but I think the visual style could do with tweaking a little bit. Lean into the "abstract" and swap the rocks out for groups of boxes. I'd maybe also try making everything shiny - increase the "metallic" setting on the shader and add a bunch of bloom, maybe? And swap around the colour scheme, I think something more vibrant and saturated would do really well, like this: https://coolors.co/palette/f72585-7209b7-3a0ca3-4361ee-4cc9f0
Minor point, but there's a bug where my high score kept increasing after I died 😜
You also need to use a better font! It'll make the whole think feel a million times more polished. Raleway might be a good shout? https://fonts.google.com/specimen/Raleway
Overall though, great job!