Armored Core: Project Phantasma Hints for PlayStation
Win the Arena easily- first equid your robot with the best generator( you win it from luke, I think)and the red laser arms.
Also equip some good missle launchers. For the battle place, choose the place that has all the office buildings inside a big square( it has blue walls).
When you start, go northwest til you see a big building ina corner. Get on top, go to the corner, turn towards the buildings, and wait.
The other AC will come over, and if you're lucky, land on your head. just look up and blast away. But if he doesn't land on your head you can drop down on him (if he's in a corner).
Some ACs will shoot at you so you'll have to move around alot.