1. Buildings should be connected to access lift. If connection is destroyed, then the building is destroyed. Both top and bottom don't have redundancy and can be oneshotted.
2. Enemies during assault spawn in the hangar and access lift. Look at your lift - enemies can wander in 4 directions. You have seen my save, in my bases enemies can't wander to the left - there's the wall, and doesn't matter if they go to the top - there's a hangar.
3. You units spawn in the barracks - the farther you put it from the action, the worse it can get. People which will spawn in the burrow near extractor would take 3+ turns to reach access lift. Another moment - if things get unfortunate, units which spawned in the barracks to the left have nowhere to run away from enemies.
4. to my knowledge you want to have hangar + access lift in each base on every difficulty below superhuman to allow all enemies to spawn, and 2 hangars on superhuman. If you don't, you will have too many enemies for too little spawn points, they would start randomly spawn around the base.
5. Your equipment will spawn in the vault, which is to the right of the access lift. Imagine that you need rocket launcher ammo, and to get to it you need to run though enemies in access lift.
There are 2 common ways to build defensible base -
1.
row 1- Hangar - hangar - empty
row 2 - hangar-hangar-empty
row 3 - access lift - empty
row 4 - corridor - empty
row 5 - corridor - barracks.
This results in forcing enemies to walk long hallway with no cover so you can snipe them. Cons - unused space, to get to last enemies
you will need to walk long hallway with no cover, usually sieges are pretty long because you constantly skip turns.
(being vertical isn't mandatory, you can mirror and/or flip layout)
2. Like in my save, surround enemy spawn point with barracks.
Your forces spawn close to enemies and you can do devastating blows on turn 1, while they haven't scattered yet, making them panic
con - enemies can get a ton of cover in prolonged firefights, though sieges longer than 5 turns usually those where last enemy is stuck somewhere and I'm skipping turns for bughunt mode.
Upgrading -
Building new facilities over obsolete buildings, like Plantations or Burrows, saves valuable time. When the new facility is small, full construction time of the old building will be subtracted; if 2x2, a quarter for each replaced building; if 3x3, one-ninth. Any refunds for the replaced facilities will be fully paid in any case.
Upgrading works on low tier living space and storage, all corridors, hangar, first prison and plantation.
