Creating a Rubric to Evaluate Games

Hello I'm wondering if anyone has any resources for evaluating student made games with SCRATCH.  I'm a Maker Space teacher at a middle school and I have students that are constantly designing games in SCRATCH which is awesome!  We have a project that includes students creating their own SCRATCH Arcade and we need a way to evaluate games to be entered into the arcade.  Any resources will be greatly appreciated!  Thanks!

Andrew