For a long time playing this game I was like "What is that 02? I got 2 bars of oxygen? Cool." I was always thinking that it was some feature I didn't know. Took me time to realize it's "O2".
Really interesting concept, got a nice sound, a interesting muti-tasking challenge. Only thing that could been better is some sort of updrage, like health regenerating overtime, bigger paddle, maybe some power ups. Great game overall.