Thank you very much for your opinion on our game, we really appreciate it
In order to get through the golden door, you need to collect all of the coins by breaking all of the chests by clicking on them, and killing all of the skeletons.
Oh. Unfortunately, that's a bug. Each door is two blocks wide. If you can't move through the first, probably there's an obstacle on the other side that prevents you from moving. Try the second block!