Wreckage

Wrecks are objects that drop from units upon deaths. If the unit suffers a lot of damage in a short period of time, it turns into debris instead. Wrecks can be reclaimed for metal, creating a dynamic point of interest on the map (for battles in the field) and providing a bit of defender's advantage.

Wrecks

* reclaim for 40% of unit's cost.
* can be resurrected by Athena or a Commander with the Lazarus Device module, for 200% of the original unit's cost, but in energy only.
* has the same health as the base unit, and turns into debris if destroyed (but overkill damage doesn't carry over).
* often blocks unit pathing and building construction, except for very small units.
* large units can crush small wreckage by moving over them, turning them into debris.

Debris

* reclaim for 20% of unit's cost.
* can NOT be resurrected.
* has the same health as the base unit, disappears completely if destroyed.
* does not block pathing or construction.
* units always turn into debris when self-destructed. This is useful if you cannot retrieve a high-value unit that is close to death, and would rather not give your enemy as much of an economic boost.

Shards

* only created from commander module wrecks, around the commander's wreck (the main wreck is left "naked").
* can NOT be resurrected or collected by a commander, only reclaimed. A resurrected commander starts with no modules.
* have 40% of the module's metal value and their health is 200% of the cost (e.g. a 100m module has 40m reclaim and 200 health).
* turn into debris when destroyed, which have 20% of the value but otherwise are the same.

Detailed mechanics

Whether a unit turns into a wreck or debris is controlled by the "severity" of its death. Units leave a full wreck if the severity value is less than 50% of their max health, debris otherwise. Severity is a numerical buffer that accumulates damage taken by the unit and dissipates 10% of its value every simulation frame (or, equivalently, 95% every second). The way this resolves is that its value will be approximately the last damage instance, unless under heavy concentrated fire, and continuous weapons such as Lotus will leave the value at about 1/3 of their DPS (so a 75 DPS laser usually kills units with 25 severity). In practice this means that burst, high-alpha damage is far better at turning units into debris than continuous damage.