Wow, a great idea! You also got so much done, considering the creative texts, quite a bunch of levels, and the final challenge! The achievements are quite funny, I really was thinking "Wow, there really is an achievement for everything", such as travelling 50 meters :).
I also like that the player often has to aim for the middle ground, collect some coins, but not many, take some damage, but not die, etc. etc., - it felt like a balancing game, which I really liked.
The final level could pose as a nice challenge even with half the length, and some waves feel beatable only when you know what is coming, but I guess it's an addition for replayability. But that's a small thing. I did however connect 24 coins on the first try :o
All in all, great work!