Sutoraika the best way to go faster is to do multiple things at once. For example, I start out going after "I can count to five." While I'm doing that, I click mute and quality, hold jump, don't die, and change colors, netting me most of the little upkeep achievements without working for them at all.
Fast path: First go for "longevity" and "get off your seats" while going 0-1-2-3-4-5-4-3-2 then suicide on the left hanging spikes. Next get 1-0-3-1-4-2-5-3-0 and then start killing yourself on the wrecking ball as fast as possible.
Finally. Made it in 10.
I think 10 may be the hard cap, because it took a lot of luck to get there, on top of only buying the artillery (by far the cheapest way of dealing with the slow red guys).
As others have said, this is a really fun little game that could benefit from just a tad higher difficulty.
4/5
 "The Enchanted Cave"){kind=icon}
 "Balloon in a Wasteland"){kind=icon}
 "Multitask"){kind=icon}
 "Phage Wars 2"){kind=icon}
 "Kingdom of The Wind"){kind=icon}
 "Achievement Unlocked"){kind=icon}
 "Shore Siege!"){kind=icon}