Hyperballoid HD

This trophy will come as you play. There are 3 power-ups that will give you extra balls: 3 Way Split, Super 3 Way Split, and 8 Way Split.

Pick up a couple of these power ups and you'll soon have enough balls on the screen. It should pop right away so you shouldn't have to worry about keeping them all in the air. 3 Way Split power-ups are pretty common, I normally get at least one per level so you should get this trophy fairly early on. If you are having problems keeping balls in the air untill you have enough, have a look at the tips section for 'The Jongleur' trophy.