You don't need to hold down the jump button to make the "ship" at the end rise high enough to reach the goal. You just need to be extremely precise in keeping the turtle in the right spot when jumping. Granted, it is *very* difficult to do so, and the level might be made better by having a larger "jump zone" for the turtle in the ship.
The level is cool. But in the end, when it says "Jump to go up", even if you keep spacebar pressed the whole time, the thing doesn't go high enough to make it to the goal. :-(