Thanks for your reply, I think I can fix all these issues and add dialogue features that you mentioned if I had time, I'm on my way to 3D world now. Thanks for spotting them!
About the number one, I surely had placed a wall collider to stop player from adventuring beyond the map, Idk why they disappeared though, maybe something went off when I was editing the tilemap. When I played I always collected all the keys and forgot about other situation so I missed this error.
Your feedback has helped me realize I should I consider other player's experiences more because I purposely made the camera zoom closer in level 3 haha, so that you can feel the danger and the agitation :D but seems like I zoomed a bit too much.