The thing about Blockoban is that it's a great game. I tried the free version and I'm stuck on level 15 (I try not to use the solutions as much as possible). With 100 levels in the free version, I will be playing it for a LONG time. Plus your icon looks nice and catchy and it occupies a spot on one of the first few pages on my iPhone because of how well it looks/plays.
I think your game looks good enough in screenshots and videos that most people would actually pay at least 99c JUST for the first 100 levels. I mean, it's one heck of a polished game, I was impressed! At this point though, your game is pretty high in the charts as a free game, changing it to a paid model would mean you're gonna have to start the climb over.
Most games don't even come with 100 levels in the full version. It's VERY generous of you to include that many in the free game, but I fear that until people complete the 100 levels they won't have a reason to upgrade. I do think that this will be a keeper on just about everyone's phone, and that long term you will see people start upgrading. So don't get down right now because I bet all those people are still trying to solve the first 100 levels. I know I am.
