When the game starts press and hold Ctrl (control), and Shift, with these both held down, press F12. The level should skip. This works on any level.
Infinite Lives
During the game, type in "Lives". You should now have infinite lives.
High completion percentage
Click anywhere you want to make a line, but be sure at least one side will not be hit by a ball. Before the line touches, use the "Level skip" code and the percentage will be higher than 100% after the line connects. Note: You will not get full score for this. Only regular scoring will occur.