LittleBrother is a simple parental control application monitoring specific processes (read "games") on Linux hosts to monitor and limit the play time of (young) children. It is designed as a client server application running on several hosts and combining playing time spent across these hosts, but it also works on a standalone host.
When the application determines that a user has exceeded her play time, it will terminate the running process. Usually, the user will get several spoken notifications (using the LittleBrotherTaskbar) before she is actually kicked out so that she can log out gracefully in time.
Note that this slave process requires a matching master process which is not yet available as snap.