Originally Posted by katsalia

Thanks for trying, but even downgrading Flash and such didn't work. I may have to give up on it. Just for example, this is what the game looks like on Firefox.

Looks like you're using Firefox with zoom. If I use it (crtl + mouse scroll up or ctrl + "+" or view -> zoom) I get the same black space that you get due to Firefox being unable to stretch flash ratio. The screen size you're seeing is this game usual display size afaik. To reset zoom in case you want to do so, use ctrl + 0.