Ah ah you're completely right and we already designed the things you proposed to add and quite a few other things.
But as you said, it was already hard to managed to get music an art working around the first game loops. the price to pay for that was a limited set of mechanic at first.
But yeah our goal was to iterate from there and add other cart, other track you can go with gold sources that would add a risk and reward choice (because simply adding "shortcut is not a valid option for me). Now we'll surely add these things on our spare time ^^
As I said in a previous comment, I also wanted to add a rogue-like gameplay ^^
But thanks a lot for your feedback, it confirms us that our other idea are aligned with your expectations :)