How do I downgrade Java 8 to Java 7 Mac 10.9.1

I was going to play a game that requires Java, but it claims my Java version is outdated, so I can either choose to 'update', 'block' or 'later'. At first I tried 'update' and download Java 7, which is the latest on the website. When I opened the pkg it says I already have Java 8 installed and quitted the installer, so I went back to my game and tried again. It still didn't work, I tried' later' this time, and then I get this message:

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Application Blocked by Security Settings

Name: gameapp

Location: http://www.arcadetown.com

Your security settings have blocked an application from running with an out-of-date or expired version of Java.

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Is there any way I can downgrade my Java to Java 7 or change the security settings to run the game even though I have an out-of-date or expired version of Java?

Computer Details (if needed):

iMac OS X 10.9.1 20-inch, Early 2008

Processor: 2.66GHz Intel Core 2 Duo

Memory: 4 GB 800 MHz DDR2 SDRAM

Graphics: ATI Radeon HD 2600 Pro 256 MB