Hey man thanks so much for taking the time to play my game, it really means so much! In regards to the bugs you've encountered, I've noted them and already begun working on ironing them out.
Some notes: I also noticed the inconsistent collision on the collectible coins. What is supposed to happen is: Your coin should bounce off the first time it hits them allowing strategic play, then it should pass through every time afterwards so they don't hinder your progress. This obviously isn't working as intended so I will fix it.
You had some really great ideas on how to expand on the levels and make them more interesting, so I'm looking into how I can incorporate some of your ideas into future levels.
The idea I had behind scoring was thus: you can choose just to get through a level in as few moves as possible in order to get the best crown ranking or you could take your time and try to get all the coins before finishing. Some of the coins are well hidden, or make you have to go out of your way so much that it makes it a lot more difficult to even finish a level. Ranks are just for a sense of personal accomplishment but in order to progress you have to find more and more coins, testing your knowledge of the levels and ability to complete them. This is also why there is no next level button, if there was sometimes you would beat a level but not have enough coins to enter the next set of levels.
I hope this explains some of my design intentions and of course I will be working hard on trying to fix any bugs I haven't mentioned here! If you have any suggestions or ideas for things you think might be improved, please feel free to let me know.