Pff it's not hard.
Tip: Do not EVER go into corners and hold down the space bar. You will for sure, at any level, any score, get a sapphire or ruby. Instead, play the game normally.
Just avoid the bubbles. Watch them and your character, it all depends on your reflex skills. Level 2-3 is still pretty easy compared to other levels. Level 7 is crazy.
30,000+ is really easy..at least, for me.