Thanks a lot for playing!
I'm really happy that somebody finally gave it a proper try!!
You are actually supposed to break the wall from the other side, you just need to bump it 2 times, just like you have to from the cracked side. As for the heart, there are 2 things that give you a hint on what to do with the heart.
First, inside the tunnel, if you pay attention, 1 enemy is too strong for you to beat, but you still do it. Why?
Second, the way the shield monsters have to be killed.
Some things could have definitely used a bit more polish and could have been telegraphed better, but unfortunately, that's all I had time for.