I've been playing since release. It's a fun time waster, if you have time to spare, you can do a level in a minute or so. I noticed something odd the other day - initially the graphics were very disappointing and basic, large blocks of colour on the characters, very little detail. 2 days ago, the graphics on my game became much more detailed and the characters coloured and detailed more interestingly. Was this because I'd passed a certain level? I didn't seem to get any notification of this. Did it happen to anyone else?

I'm also torn between using coins to open up new areas (and characters) or to upgrade characters. I can't seem to get too far in the game without doing both.