optimization for a breakout

I made a breakout game based on the tutorial (Cloning the Classics"Breakout"), game is working flawless, levels and scores and everything, problem is when trying on android, it has high draw calls and drains battery usage fast, on lower or even medium end phones it stutters as if the phone is chocking, any advice on lowering collision detection and draw calls?

Here is a screenshot

All Levels are arranged in someowhat similar way but the number of crates varies.

I am still stuck on this one and cannot release my app, any help or tips would be much appreciated.

Have you gone over the articles on optimization and not wasting memory? Also the ones on collision cells and collision detection would be good to review as well.

I went through all, but thanks for your reply I will go through again just to make sure I did not miss anything.