Is this a sequel to something?

[Bosuonparedo]

The title makes it sound like there was a "Rex: An Island" or something before this game.

Also is it possible to get an option or cheat code or something to allow you to play in zoomed-out mode all the time without holding X?

[redspacebeast]

It doesn't appear to be a sequel. There's also no option to play zoomed-out all the time, unfortunately.

[A_Phosphorus_Invention]

I think the "Another Island" is a reference to "Another Castle" from Mario Bros. Or maybe Mario Land.