It looks really good and the gamefeel is quite juicy ! Really good effort on the UI as well as putting some voice acting ! I agree with amptomp, tweaking a bit the looks of the arrows to make them more distinct from each other would help. Otherwise it's really good !
The game broke twice for me however, I don't think I've done anything particular to cause this, the browser I'm using is Firefox if it helps. If I press Shift to start a new run when broken, the next run is broken too. If I go back to main menu and restart over, everything is back to normal.
It seemed to happen after several runs each time, I'll try to describe the issue as best I can :
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Starting a new run, the first jump I do, my character duplicates, I have an additional character jumping out of mine basically. The game started lagging a lot when that happened. I get two characters on screen, I control the original fully, and the duplicate jumps when I jump but doesn't move to the right so he gets left behind quickly.
After gameover, I start from the duplicate character's position and I retain the speed gained from delivering packages of the previous run. Then when the runs ends either by falling into a hole or by running out of time :
A new run starts and I get this. If I press D the screen still scrolls to the right, and it seems there's still a character present because when there's a hole in the middle of the screen, I get the gameover message from falling into a hole.
I kept on pressing D and was able to go past the boundaries of the level :
Hope this is enough to help you find what causes this !