This game is kinda glitchy. I've had my character fall through the floor three times. I've also left the screen for a moment, returned to it, and found I've no idea where I am. It doesn't even look like the same level.
Are there items you can use, that count as a second launch? If not, it seems there is an issue with the achievements, because my best is over 3 million feet, but it hasn't recorded that. This game however is crazy fun. I highly recommend it.