Yep, the controls may have been a bit unwieldy.
Additionally, if you were playing on fullscreen, the player speed may have been significantly faster than intended, due to a wierd interaction between Unity's screen height and itch.io's fullscreen. That could be the cause of your problems handling the cart, but of course it could also be that the controls aren't the easiest to get accustomed to.
Either way, thanks for the feedback, much appreciated!