Ratchet and Clank: Size Matters Tips
Ok, for this one, you must have a titan Electro Rocket ver. 3 or higher. This can be done on Challax. You equip your Titan Electro rocket, hold the circle button down for at least 5 seconds. Then when A guard comes, aim at him and release the circle button, the guard would be killed and the rocket would go through him, killing him in the process!!! (Must be in Challenge mode) I tried it, and every time it worked for me!!