Is there a way to use a sign like for instance if you right click a shop sign, it would open a door or activate something? I am building a type of machine that requires you to pay to get it to work.

Nice! I love puzzles like this.

Seem to be stuck on the second room though. Either I can't figure out where I'm supposed to click to input an answer or it's broken. Two of the signs have the same writing and one of them has an &4 showing <object class="emojione" data="https://resources.enjin.com/1489581540/themes/core/images/emojione/svg/1f61b.svg?0" type="image/svg+xml" standby=":p">:p</object>

I'll keep trying as battery life allows.

Edit: My perseverance outlasted my battery. I made it through there and got hopelessly lost in a later room.. I'll try again later tonight!