(for Dark Days of the Dead) ACHILLES_HEEL_STRICT and ACHILLES_HEEL flag for enemies

[I-am-Erk]

Is your feature request related to a problem? Please describe.

I have left Dark Days of the Dead sitting for a bit too long, thanks to COVID.

DDotD is supposed to simulate a romero zombie movie. It actually does this pretty well in many ways, but it is missing one very important thing: Zombies are way too easy to kill. The goal would be to have a nearly unstoppable horde that slowly advances.

Describe the solution you'd like

You must destroy the brain!

Add two ACHILLES_HEEL flags to enemies. Enemies with this flag:

• Only take HP damage on a critical hit. In ACHILLES_HEEL, massive damage sufficient to gib the target also counts. In ACHILLES_HEEL_STRICT it does not.
• Damage that isn't a critical hit or gib-level attack instead reduces the target's move.
• If the target's move is reduced to zero by damage, it is knocked down and stops taking further move damage.

ACHILLES_HEEL_STRICT only allows damage through critical hits. ACHILLES_HEEL allows you to harm the enemy with HP damage with effects, so that they can be lit on fire to kill them.

Describe alternatives you've considered

• Eventually CDDA core wants a more complex damage system that might be able to flex into this system with some data-driven stuff, but I'd like DDotD to be properly set up much sooner and I don't think this is a big ask.

Additional context

• I also want to be able to increase critical hit chance for DDotD, and to allow a Coup de Grace if you melee a knocked down zombie. Those can wait though.
• It would be lovely but unlikely to have a way to turn a zombie into a crawling zombie if it received high but not massive damage.
• This could actually lead to some interesting enemies in core DDA as well.

I suspect if I could get the DDotD feel working right, I'd be sufficiently excited to start working on a special storyline pack for it.

[Giagantic]

Make a Zombie like the best Romero Zombie:

TARMAN

Though if you really want to nail the Romero vibe make it so the only real way to destroy them is to incinerate. In Romero's film Trixion 2-4-5 will infinitely reanimate flesh, meaning that even as a head it will still seek out brains. Not sure how you would go about doing this, but it would definitely be interesting if you could pull off having a zombie being cut in half only for both halves to continue to assault you.

[I-am-Erk]

That's a russo zombie.

[dchieh222]

This could improve tactical options.

[I-am-Erk]

Weakpoints are better and already almost done.