A better way to do the 300 is to get the grenade launcher and max it out but in place of gunners get the quake tower and max it out too. I beat it without getting hit once.
I jewed 23 by putting the rotating thing in just the right spot above the second fan, then it hit the first red ball 3 times and on the third time if falls in between the metal bar and the fan. Then a bolt placed just to the left of where the ball fans keeps it from falling left and it goes straight down and hits the dominoes.
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