The Last Shelter Mission 13 Guide
Mission 13 begins immediately with legion of bugs just keep pouring in non-stop. This mission only has 1 wave though, so at the moment you notice the King Bug (with yellow stripes), this indicates is at the nearing end of bug wave. Just build 2 Energy Unit and max upgrade them. Secure the top with some Laser Guns and Heavy Weapons. Immediately sell towers when they approach their limit (10% health) to avoid losing a star. Sell those towers and use those funds to fortify the base.
Mission 13 Final Layout
Mission 13 Playthrough