I really like the skeleton here, if you're able to come back and polish it up and finish the story after the jam, I think this could be great!
Starting off with the good, I really love the artstyle, feels very 2000 to me, reminded me of JSR and Katamari. I think the premise is fun, speed running platformers are normally a pretty safe bet. Love that you were able to make a version of Bijou's new model, (though I hope that wasn't what ended up leading to the lack of time to finish the rest of the game...), and I hope that you can expand the power up system to include more cool abilities, the effects on them already look really nice, so it'd be cool to see what else you could come up with. And speaking of effects, the SFX are pretty good too.
That does segue me into where I think this project could grow some more - the pebble collection system is fun, but I don't think there was any special effects when picking up a pebble compared to a power up (cant go back and check since I got them all - even after deleting the file and re-extracting the zip) , its a small thing, but its also an optional system that the player should be rewarded for interacting with, even if its just a special jingle. The in air movement feels a little too sluggish for some of the precision movements needed to get the gold medals on the missions, so that could either be tweaked, or the time could be reduced, and some additional SFX for meeting those requirements would be awesome, seeing as you're already tracking the best times, a check in the end screen comparing the values should be quick. Lastly, the timer still counts up even when the game is paused, which is not great, to say the least.
But like I said, I think there's some great bones here, so it sucks that you ran out of time, would be cool to come back and see if you've added more content in the future, because there's definitely a niche here, and I'm sure Biboo would love to check it out on stream! Good work!