Hint: Energy Sword In Outskirts
Do-able on cooperative mode. Fight through the stage to the Hotel Zanzibar (hotel next to the Warthog ride on the beach).
There is part of the hotel's building that is burned off. There is a ledge that you and your buddy can reach. Jump on your partner's head. Notice that there are pipes sticking out. Jump on one of the pipes then walk back in the little area.
Have your partner kill himself and respawn where you are (plasma grenades are best - throw straight up, and then stand on it). If you are quick, you can also use the sniper rifle and kill your buddy, then move quickly back to your spot. Make sure you (the guy on the roof) move far back enough to make the buddy spawn next to you.
Once that's done, both of you walk back out on the pipe and do a partner jump (one guy on top of another guy's head). He/she will have jump on the roof closest to them. Kill the lower player and respawn next to the higher player.
Walk futher and futher down the roof. Turn left where the roof turns and if you keep walking straight, you will come to the part where you fought the aliens and those jackals in sniper alley. Turn left again where the roof turns and walk straight but don't jump off to the lower roof. As you walk you will see a big hole in the roof somewhere. Look down and there will be a plasma sword with full energy.
Subject: Energy sword in outskirts 
Tue Apr 27, 2010 3:45 pm
