The points to get for the achievements are insufficient to unlock all levels. So you can only complete this event by spending 25 tokens on at least one level.

The total number of points to earn is 1230 (add the numbers for all 27 achievements).
The total number of points for all 15 levels is 1350 (starting by 20 in incrementing by 10 per level, so 15 x (20+160) / 2 = 1350).

I think it is unfair that you can only complete the event by spending tokens. We are supposed to win something, instead of spending,