Sorry you felt this way, the game could definitely be better but you have to remember the time constraint that we had to work with (which for us was barely 2 days, not 7)
There were a few SFX, although did get overshadowed by music, which is why I thought to not worry about that too much, that and the juice that you mentioned, I guess more animations and effects would help
It's not that we forgot, just wanted to get the soundtrack, basic mechanics and the background artwork right before the rest, which in itself was not perfect either with the camera not following and the spikes problem
Storytelling was not really the main of our focus so it's probably not the best
Checkpoints I regret not spending more time on since this and the spikes would probably make the game a lot more enjoyable, it was a last second thing that I could not finish (because duplication made it 10x more difficult)
Thanks for your feedback, I really hope that after the jam ends you'll play the game after it gets updated, with all of the problems you and many other mentioned getting fixed!