I agree with sathalom that the jump needs some sort of visual feedback.
I spent a long time stuck in the bottom area trying to figure out how the jump worked.
It's very different to normal jump mechanics, which makes it interesting, but also means you can't rely on the player's knowledge from past games to figure it out.
I would suggest limiting the charge at some point as well (or lowering the limit if there is one) because I did some confusing bouncing at one point.

I also personally prefer the inverse to the timer setup that you've used (second game in this jam that I say this to).
Instead of counting down as an end condition, I would prefer it if you counted up.
Then your score is not the number of deliveries, but how long you took to get them.
That way slow players like me (2 deliveries, *almost* 3) can still see the whole game in one playthrough, which would let us try and plan better for the next run.

Aside from that, I don't really have much else to say.
This is a solid jam game that feels complete.
A lot of jam games end up feeling unfinished, or broken and buggy to the point where they aren't playable - which this was not.
I see this was your first jam, so you should be very proud of that.
:)

Oh, this last part could be a "me problem"; but the first few times I tried to play your game I couldn't run it.
I got an error talking about Microsoft Visual Studio runtime 2015 not being installed.
I Googled, and tried to install it, but the installer said it was already installed...
Then, I played a different jam game a few days later that had a similar complaint, but the game offered to auto-install for me.
I tried your game again immediately after, but it didn't work at the time; BUT, today it mysteriously worked for seemingly no reason...
I haven't developed in unreal very much; but it might be worth checking if there's a packaging option related to this.
If not, then I don't know... my PC had ghosts this week.
¯\_(ツ)_/¯