Sad to hear you soft locked, good thing its not a big.
I know there were a possibility to soft lock, but I tried to create the level so it would be hard. I don't think you can softlock if you only use the bombs on cracked walls though given you pick up all bombs.
There is a minimap, you just didn't find it. Its an item you pick up early in the game.
The coins purpose will become clear at the end. Thank you for playing.