Upgrade shop is crazy, you will stick to the first 3 slot heli for the last 80% of the game. Buy sonic shot and keep upgrading it rather than investing in another weapon.
Everything else seems to be a waste of money.
The most important upgrade is the beaked head. Fireballs stay on the stage forever. Place a fireball at each edge of the map and you will never encounter tanks. You'll also always need an ice skill for planes. If you hold space at the start of a level you will go off-screen and be invincible. This plus spider eyes will win skull-collecting medals (activate the skill with your mouse).
Scoring is very confusing: "You traveled 1757 meters ... You only need to run 2922 meters more to be first!" according to the hall of fame the top for the day is 2382.7, and the "max distance run" on the achievement pane is 100x the distance run... what?
Name: the number one mage in the world, book be damned! Great Mage of the realm
Suddenly I've lost interest in pursuing #1 rank in the book and the title of Great Mage...