Is there any "adventure" style games that are simple enough for a just-started-gamer at age 5?

We have Lego Star Wars, but that is hard for ME, never mind my son.

So I'm wondering if anyone know of a more "begginner" / "kids" level game that my son can play on his own, rather than screaming for mum or dad to help every 2 minutes.

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Mats