And if Wikipedia is to be believed it's presented in a eye wateringly high resolution of 112p.
This high of res.
Edit: Of course the bit rate was pretty damn low as well. Here's a comparison video I found. This comparison uses the higher bit rate version from the Shrek GBA video cart not the Shrek+Shark Tale video cart though so keep in mind, this is the better version.
Exactly
It's honestly impressive they even were able to do it
Yes, there were way more efficient ways to store video on the go in the 2000s, like MiniDVD players with tiny screens. The codec is in firmware and the video format and medium is standardized. It’s the easiest way to sell small, cheap gigabytes of storage if you need no quick random access. And the family might already have the more useful laptop-like portable DVD player with a full-sized drive and almost every home video title was available on those.