While I love this game I can definitely tell the developers are going to get their coins off you. Once you relaod the diamonds..ie pay for them its like u have to use them to pass levels. Like I could be playing a level and the people will be coming one by one vs. multiple which makes you run out of time and therefore have to use the diamonds to continue or you'll lose all your gained items. So while the game is free you def won't make it pass certain levels if you don't buy more items.