Item description:

The Gunner / Reach the highest level (LVMAX) in Gunner's Gauntlet:
Your current level is lv8. Start the minigame and make it to the last (fourth) waterfall with at least 1 volley ammo. You get it from Bicocette (small purplish armored fiend). This is the blind spot! As long as you stay near the fence, enemies will not attack you.
Keep pressing circle for so-called dead-click which marks all enemies, even though they may leave the screen.
When another Bicocette appears, shoot the Volley and quickly run, to the chest left behind by Bicocette to get another Volley.
Repeat until you have 40 seconds left then run to the beach. If your score exceeds 2800 points, you get the trophy.