15/25 Minutes in Rush?

[PixyJunket]

So I had basically a perfect run in Rush the other day.. I reached level forty-four, maxed the score counter and I had only one death at the end.. yet I BARELY scored the 10 Minutes in Rush and Survive 10 Minutes achievements.

I can only surmise that the "secret" to Rush is defeating cubes, which give +25 Seconds to the clock. But how can I get more cubes to appears? I barely crossed the ten minute mark so twenty-five minutes seems like an impossibility unless there is a trick to have cubes constantly spawn.

[midori]

I got the 15 minute one, and let me say it's nearly impossible lol. Gotta be goin crazy killin stuff as fast as humanly possible, screen clearing nonstop for 25 minutes. I've come kinda close but ya it takes a lot of practice. Extremely difficult achievement.