Firefox started blocking Flash player last year. They may have relented for a while, but I think it's blocked again. Here is a list of Add-Ons that Firefox blocks.
https://addons.mozilla.org/en-US/firefox/blocked/I'm not sure if Flash will work if you use IE. It might depend on what version you have.
Don't try to install an old version of Flash Player on your main Windows. If the latest version of Flash won't install through your browser, see if you can download the executable for the latest version directly from Adobe.
You might have to add the exe to your antivirus's "exceptions" list.
This problem with Flash may be why the game was removed by Big Fish.
I'm not sure, but the only way to play this game now might be inside a virtual machine with a non-updated version of Windows installed. Then the game will be able to use the old version of Flash that it shipped with.
Lots of web browsers and security software seem to be blocking Flash because there are so many zero day flaws in Flash -- new ones discovered every day -- which means they can't be detected by an antivirus. Considering the seriousness of ransomware, there is reason for doing this.
On my computer I see Flash was available in Firefox version 44.0.2 but not in Firefox version 45.0.2, so I think blocking Flash may be a new "feature."