Check that. Just hit 593.5. Thought for sure the penguin was going to take a header into the snow, but it skipped along nicely. I'm kinda thinking 593.5 is the maximum you can get, seeing as how no one has gotten it to 600. I'll try for a bit longer though. For scientific research, of course.
I was dinking around with the full screen version last night and was able to go 588. My 6 year old daughter came to kiss me good night and wanted to play. I told her she could take three whacks and then off to bed. She took the mouse and on the third try went 602! I stayed up for another 30 minutes trying to bash that damn penguin past her mark, but never got close.