1st Timer.....

I have never played this type of game before and figured why not give it a go....I have really enjoyed this! My only problem is after I have finished a level I find that I have to repeat it again, why?? This has happened quite a few times now. I also am questioning what the deal is with the speaker icon, it serves no purpose so why is it there??

Scooterjuice about Find the Difference 150 levels