Buy the first few items in the shop (don't forget to buy the pre-loader and save feature, they're the most important.) then you play the game and beat the twenty levels. Since you wont have the money to upgrade you press play. After each level attempt you should upgrade yourplane thing. Keep doing this until you have 12 fully upgraded parts on your plane thing. Don't forget to buy the rest of the items at the shop and upgrade them. After you've done that go back to the shop and buy the upgrade that says mystery. After you do that the game will take all your money and you'll get the final achievement. Afterwards you can keep playing or start a new game game and do the same thing all over again. Thanks for reading my walkthrough.
Thanks, that pretty much help me. I finished the game like 4 times with your tips, thx!