I like firebats over the hellions for this mission, they are easier to heal, and dont do stupid things like speeding ahead of your group to get overwhelmed. Having unlocked siege tanks will really help with the defense too, 3 on each entrance will wipe out just about anything before it touches your bunkers. Going out at night is not reccomended, espically after aberrations begin appearing, getting the infestors is best done by clearing the structures near them during the day, killing them very quickly at night, then running back to base. Attacking during the first 2 nights can still be effective as long as your units are sticking together and you are keeping a careful eye on them, but if things start to go badly your probably gonna be trapped and lose all your units.
I stuck in this mission speed run for a week...(Since I hate posting the mission's video with more than 4 parts. And my previous record is 47minutes...) Lastly I found some tips to finish this mission fast =] 1. Longer time passed, harder wave to your base. 2. If you are fast enough, you can keep the bunkers money of top left and bottom left side for more marine. (At night 3 its very easy, not hard at night 4, a little bit hard at night 5.) 3. Protect 4 default Supply Depot. 4. You won't need too much Hellion. Just keep making 7-8 marine and 1 Hellion. 5. At Day 1 (AND the very first 90seconds day) try to destroy structures which are located at the top half side as much as you can, structures with light hp ARE recommended. Those structures with heavy hp could be destroyed at Day 2 by some Hellions. 6. DO NOT try to destroy ANY structures at night on Brutal mode, its wasting your soldiers and time. I done that achievement in a tactics experiment and found out its impracticable. 7. Try to upgrade your marine in game during as fast as you can. 8. Try to team up your soldiers (of course your buildings too) with hot keys. It save your time so much! If you are looking for the bonus objective, here is a tip for you. After your team cleaned the bonus area at Day, just leave 4 marines there.
I like firebats over the hellions for this mission, they are easier to heal, and dont do stupid things like speeding ahead of your group to get overwhelmed. Having unlocked siege tanks will really help with the defense too, 3 on each entrance will wipe out just about anything before it touches your bunkers. Going out at night is not reccomended, espically after aberrations begin appearing, getting the infestors is best done by clearing the structures near them during the day, killing them very quickly at night, then running back to base. Attacking during the first 2 nights can still be effective as long as your units are sticking together and you are keeping a careful eye on them, but if things start to go badly your probably gonna be trapped and lose all your units.