John Garvin of Sony Bend has posted nine different "must do's" for players to, well, do when playing Resistance Retribution on PSP.
If you have not played the game, don't take a peek after the break or hit this link.
It'll pretty much spoil things for you.
Sony’s Must-Do List For “Resistance Retribution”
(Third-person shooter, PSP, March 2009)
1. After you get rid of those pesky Leapers in the Rotterdam canal, try going back into the sewers for a neat little surprise. Do this again after you raise the water and it will gain you access to a room you couldn’t get to before.
2. In the conversion center in Rotterdam, after you crawl through the pipe leading into the next storage room, charge your Razor and shoot the alternate fire through the hole in the glass. It will bounce around and hit a power cell, which destroys the glass and gains you access to some hidden evidence as well as grenades!
3. I know getting close to any of the Armored Titans can be scary, but if you have some shotgun ammo, run up to them and shoot them a few times with the alternate fire mode. The Shotgun alternate fire cuts through them like a warm knife does to butter!
4. Once you have Mallery’s Auger, use that shield quite often as it bounces enemy attacks back at whoever shot them. Makes things a little easier in rather tough situations!
5. Remember that the Auger multiplies damage depending on how many walls the shot goes through. Even putting up a shield behind a wall can add to the power!
6. Collect all Intel to unlock bonus weapons necessary to achieve all the skill points.
7. Listen for all the voice and movie changes while playing in Infected mode.
8. Hijack the small worker drone in the second Trench level at the end of the lava cart ride by shooting it with the auger so it brings you the unreachable Intel.
9. Second Hammer fight too hard? Lure it under the plasma dischargers and flip the switch on the upper decks to zap it for damage and momentarily stun it. Stunning it will allow you to get behind it and inflict heavy damage to the power core on its back.