In a Barrel - Achievement / Trophy Guide
When you have to pass a jumping Jawfish, shoot him on his first jump immediately after you have pushed out the firefly bait.
Military Machine - Achievement / Trophy Guide
Just after you unlock the Power Transfer Bypass (your gun's semi-automatic mode) you will encounter a total of six security droids patrolling the area to the right. You must destroy them quickly, within seconds of each other. The last droid may randomly duck behind cover. If this happens, reload the game and try again.