Instructions
Understand how to control Daxter before starting your exterminator missions for Osmo. Press the "X" button to make Daxter jump, the square button to swing the fly swatter, the circle button to spray the bug spray, and the triangle button to make Daxter crouch when moving him in any direction, using the control stick.
Start at the Westside Hotel and collect 25 gems throughout the level to advance. Swat or spray any bugs that get in your way. In the next level, the construction site, kill all of the evil villain "metal heads" by jumping on their heads. Complete the mission in Breeze Valley by killing 26 bugs within the time limit.
Complete the missions in the brewery (where you find Jax) and the transit system (where you must race a small "zoomer" train to defeat the boss). Defeat the Hive Queen by spraying her with the bug spray in the face when she shoots the laser beams at you.
Get all eight eco crystals to defeat the Strip Mine mission. In the Mission Valley II mission, spray the bugs with the green eco spray to save them from enslavement to the Queen. Complete the rest of the missions, which are similar to the previous level but with more difficulty and extra missions to complete.
Go to the Prison for the last level and make it to Kaeden, who is the final boss. He turns into a giant insect. Attack him with your weapons once he is in close range, after the purple mist is no longer around him. Continue to shoot Kaeden until he gets weak enough that you can swat him on the head to defeat him.