Tips and Tricks
Completing the objectives will give you nice amount of coins, and it unlocks a new set of objectives for that level. If you want to unlock new levels, you must first complete a set amount of objectives on previous levels.
Use disguises you will unlock while leveling up. They change the appearance of your head and offer you different kinds of bonuses.
As in most platformers the best overall tactics is to always be on the move and learn how the bad guys move as well.
Try and lure floaters up onto platforms, then you can shoot them from above. Patience will prove rewarding.
Find places where you can rack up kills quickly without being put in any danger.