picking up money takes waaay to long in the later levels, sometimes u have to hold the mouse in one place for over 5 seconds watching how these stupid coins circle aroud the pointer.
save/load-glitch: if you leave the kongregate-tab with the game loaded while playing on the elements homepage, you can, in case you screw up, close the elements tab and go back to kongregate. Now do something (buy a pillar) to make the game save (look for the green blinking button in the top left) and you get your old status back.
first: play insane until u upgrade everything ^.^ second: try to hit the ball with the very edge of the paddle, since the vertical speed remains the same, the ball will go with the speed of 5-10 times its size per frame and most likely tunnel through the enemy paddle (or just go through the wall and dissapear) this way you can earn like 100 points with the first two balls
insane is actually the easiest mode, without even moving i get over 500 points and 80% accuracy, while on normal i cant beat the challenge and it took me 3 tries to win.
to sum it up: CRAPPY COLLISION DETECTION !
... and what is the sense of upgrades if your opponent gets the same improvement for free?