itch.io

There are multiple ways to fight her, depending on the quality and quantity of your gear, and here are some of them:

• Spread out your units in a way that some of your units draw out Fai's (heavily-armored boss of the level) fire, while the others attack her from the flank. Her armor is strongest at the front and weakest at the back.
• Explosives work well in damaging armor. If you don't have enough grenades, lure her into the explosive barrels in the level and shoot it when she's close to it.
• There are landmines in the level that you can pick up (by dragging and dropping to your inventory slot). Then you can right-click on the item to plant the landmine on the current position. Lure Fai near the mine, and it'll go boom! 

Best of luck, captain!