If i was you i would make sure there aint no magnets around it. The screen often changes res because the games run at 640x480 even when they say they are at a higher res (they use emulators so its diff). Its nothing to worry about and when It does that just reset the thing and it will be OK.
As for the wiggling, we have a monitor that did this but it seems to be ok. It would go wiggly for a few seconds and then go back to normal and this was usually when it had just been powered down by the computer and i think this is when the monitor is trying to fire all the pixels at once in an attempt to start up. I wouldn't really call it a big deal........just dont sit too close
Hope this helps
Andy
P.s. If its wierd colours that means there are magnets nearby (big speaker maybe?) anywho get them away from it. It is fixable and we have this cool little thing where u just put it by the screen and it fixes it all.