Easy "Smash" Achievement
You have to deal blunt trauma to enemies by throwing rocks or other objects on them. Play level 8 and go to the checkpoint with Harpoon Mech. Get in, and pick up an object. [Shoot] fires the harpoon. Hold it until the object is near, aim at an enemy, then release [Shoot]. The object will fly towards the target. Some objects will fly straight, and others will fly in an arc. Use the harpoon to kill as many enemies as possible, When it is destroyed, intentionally die and you will reappear near checkpoint with Harpoon Mech. Repeat the process as many times as desired. Note: Killing robots may not qualify. Also, do not use other checkpoints after Harpoon Mech or it will become unavailable. Walking past checkpoints is acceptable.
