This is the first game app I've seen that purposely sabotages game play with ads. Between level ads, I get. But when the player is concentrating against an unreasonable time limit and trying to remember where pieces are located, when without warning there's an ad, followed by the game on pause, that's clearly done to disrupt the player's rhythm and focus. I can only assume this is to get people to buy credits to keep the level going. This could have been an enjoyable little pastime.