Recently, a pair of screens for the PS Vita and 3DS versions of Time Travelers popped up online. Unfortunately, a screen for the PSP version did not rear its head, but the PS Vita and 3DS snaps do allow us to compare Sony's and Nintendo's current gen handhelds.
The Vita screen does look better, but the game doesn't seem to be pushing either handheld to their fullest. I'd like to see a screenshot of the PSP version too, because I suspect the game may be optimized for it.