Defense Bunker

"Want some extra protection from attacks? Send units here to protect your planet!"

— in-game description

About

Units placed in Defense Bunkers will come out during an attack and defend your planet!
If destroyed, the units placed inside will also be destroyed.
You can only put units in your Warp Gates into Defense Bunkers (can't put Green Berets)
Costs 1/3 the price in Minerals that the unit cost. For example, if a unit costs 30,000 Coins to make, then it will cost 10,000 Minerals to put one unit inside a Defense Bunker
Falcons, due to their attack tactics involving fly-bys, are able to destroy targets anywhere on the map (assuming there are units along the way).
Completely useless if empty.
If units in the Defense Bunker are outside of it when the bunker is destroyed, they will continue to attack until there are no targets left.
Units are not lost between upgrades.
Bunkers continue to function (if there are units inside bunkers) even when they're being upgraded.
Colossus is very slow so put some falcons with them
Falcons in bunkers are the best in destroying S-Trikes, due to S-Trikes being unable to target them.

A good way to destroy a Defense Bunker's defense abilities is to use Battle Support on the units as they leave the bunker.
Two Boulder Strikes can destroy a level 3 Defense Bunker. One Boulder Strike will destroy a level 1 and 2 Defense Bunker.
The most effective units to put in Defense Bunkers are Falcons and Colossus. If you don't have the time, Wasps (level 6) also work well.
The most effective method to destroy bunkers is to use S-Trikes and Starlinators. If you are able to clear a path to the target, then S-Trikes alone will do. Place the S-Trikes one by one, making sure they hit the Defense Bunker. Eventually, the bunker will be destroyed. If you are unable to clear a path, use S-Trikes to distract the bunker units and use Starlinators to attack the bunker. This will work most of the time, unless there are Falcons inside the bunker.
Put Bunkers on the angles of your village because already some opponent likes to put units on angles and it avoids the skulls nuclear on Bunkers at the same time.

Level	Building time	Cost	Health	Capacity	Range	XP	XP if destroyed
1	6h	437,500	10,000	380	455 (41.36 tiles)	1,181	114
2	12h	2,000,000 1,687,500	24,500	450	515 (46.82 tiles)	6,717	662
3	1d	4,000,000 3,000,000	50,000	540	580 (52.73 tiles)	13,111	12,92