Haha, yeah I switched the bottles back and forth every day till this final stage - the difficulty is raising with each wave by a random number between 0 and 2 - so it can be 12 ghost at wave 6 or it could be just 4 - but I know what you mean - I played the game severall1000 times and know it very well so I feel like - if I make it a bit harder and ... well other player who did the first time said it was to hard xD