All of my master systems actually have this built in. It is a pretty cool bonus for sure!Some models don't have a built in game or have Sonic the Hedgehog instead. I had a SMS when I was a kid, and my sister's dad had one too; mine had Sonic, his had Alex. Was fun, although also trying to play [insert any other game here] but the cart was being iffy and so it just booted up into Sonic was a somewhat frequent annoyance.