@UltimateRuler: Yes - just build lots of solar panels (about 3 or 4) and about 4 energy stores. Then as many fully upgraded THELs as money can buy. But, don't buy the THELs until the energy stores are almost full or until the ships start coming on screen.
LeoN: That's true but there are also levels which require less than 3 balls to complete it all balances out so that the game is completable. It IS possible to complete the game - I know someone who has, but I can't do it myself.
You can save levels as comments. To select a level start highlighting the line then drag the cursor straight down and copy.
3.1,269,174.0,188,173.0,225,110.0,312,99.0,350,165.0,230,255.0,324,252.
Bugles - place a combonly near a combo, then click it when it turns the colour of the activating tower. They rule because you can fit more combonlys in the range of a big damage up (among other things too).
 "Fear Less!"){kind=icon}
 "Pirate Defense"){kind=icon}
 "The Space Game"){kind=icon}
 "Neon Disks"){kind=icon}
 "Neon Disks 2"){kind=icon}
 "Global Defense System"){kind=icon}
 "Find The Squares"){kind=icon}
 "Bubbles 2"){kind=icon}
 "Onslaught2"){kind=icon}
 "Amberial: Nebulosa Realms"){kind=icon}
 "Phoenix"){kind=icon}
 "Mezzo: Winter Edition"){kind=icon}