I have played this game and have gotten way above the 450,000 needed. However, after the required amount is achieved the timer continues. What happens is that the extended timers and bombs keep adding to the time and you just go on and on. Then what happens is that you get more time added but still have the bombs ready to explode. You can't beat it. My opinion is that once you reach the required amount for the level that the level is done and it completes. I've had this happen on other levels that were much like this and you have to work at keeping the bombs from exploding and NOT gaining time so it finally ends. This is frustrating to say the least.
