Card 19 or Health Regeneration is a Permanent Bonus Card, which grants the Plane the ability to slowly regain lost health.
In-game Description[]
Coating the hull with shape memory fibers will slowly repair any damage your plane receives while on a mission.
Function[]
Upon acquisition, the Card enables the Plane to regenerate missing health points during Stages at a rate of about 1% of health every 1.5 seconds. Therefore, the Card will not be activated when the Plane is at full health. Since the HP value is displayed every time the Plane regains health, the player will be able to see the Plane's health at all times until their health is full.
Unlike Health Restore items, the regeneration rate of Card 19 is not affected as the player upgrades the health degree within the Loadout screen. The same applies to Iron Clad and Swift Justice despite their different in maximum health points. The Card and its regeneration have no utility if either Ace of Spades or Limp Berserker is used, both of which has the "ridiculously low health" factor that makes them one-hit kills.
Summoned Wingmen during Stages are never affected by this Card.
Strategy[]
Card 19 is one of the most powerful Cards in the game, mitigating the reliance on Health Restore items, which sometimes can be hard to come by. The passive regeneration can help the player recovers health completely even after a near-death blow from enemies or in the case of a successful Lucky Shield activation after a decent amount of time. The healing is especially important on Tournament Stages, where items are less likely to drop than on normal Stages.
Since phases of the Bosses only progress after all of their armaments are destroyed, players can spare the last few defenses of an easy phase in order to buy time and regenerate most health in preparation for later harder ones.