Ratchet & Clank 3: Up Your Arsenal

This one is tougher than it looks, as there are tons of security robots firing at you and hardly any zappers. For this reason, I suggest waiting until after you find the holodisk and return to the planet to get it. On your return trip, there will be far fewer security robots and much more zappers. You'll also want the Level 5 Suck Cannon, as the flaming fireballs it shoots will help immensely. Keep in mind this not only has to be done in one run but sucking up the zappers with your Suck Cannon will count towards the 40 you need.

Once you return, run past the Security Robots and suck up the zappers, shooting the nearby robots with them. Once you get to the big plaza area, suck up as many of the zappers as you can and fire them at the huge robot (which will sap most of your health). Use your spare ammo to destroy any lingering robots and go into the tunnel, sucking up more zappers. Destroy the three flying robots and the huge robot then go up the path. If you've been diligent, you'll unlock the skill point somewhere around here.

Keep in mind that you can still suck up enemies with ammo in your Suck Cannon. Press Square to swing your wrench and then press Circle to start sucking up enemies. Good luck. It took me a couple tries.