Needs a tutorial. I nearly gave up entirely, but finding the gold mine gave me the motivation to interact with everything, and so I did end up defeating the skeletons.
Not much of game to be honest, and it is confusing what triggered the death of the enemies. Still, it shows that you have use some type of event/trigger system, so to me it looks like you didn't have the time to complete your project. It's a good idea, and I genuinely hope you keep at this.
And heads up, you don't have donations enabled on your game's page. Keep it up.