There is no Games category of plugins in Spark, so currently it would mean disabling them by name. Which is not optimal. I have filed a few tickets describing a more broad solution, but as it is more complex, not sure if it ever will be implemented.
[OF-1372] Add option to disable selected plugins in Spark via Client Control - IgniteRealtime JIRA
[SPARK-2005] Add option to disable selected plugins via Client Control - IgniteRealtime JIRA
For now you can just remove plugins from the installation and users' profiles, disable them in spark.properties file or maybe even via default.properties creating your modified spark.jar file and distributing it for your users.