The screen on mine was really badly scratched, it looked like it had been chewed by a dog, in fact I believe it was (I found the phone on the street, locked with no SIM and nobody claimed it for over 6 weeks).
I attacked it with wet & dry sandpaper from 400 grit right down to 1200 grit, then polished it with car lacquer cutting compound. The screen now shines like new, no more ugly scratches. I might do the whole case next because even that looks nicer after sanding and polishing.
The cheapo plastic screens on these things scratch very easily, but can be restored with some work. So if you actually like and value it (I must say I really do not like these kiddy phones, far too small and infuriatingly complicated for me!), then you might want to use some protection on the screen.