commit 9c9518fdfc83b5ee7844dadda380209242e3fc9d
Author: Dino Bollinger <dino.bollinger@gmail.com>
Date:   Sun Feb 6 11:18:41 2022 +0100

    Duke3D: Introduce actor event 'EVENT_PREACTORDAMAGE'
    
    This event is executed when an actor runs A_IncurDamage(), and is
    placed just before subtracting 'htextra' from 'extra' and updating
    the actor's owner (i.e. just before damage is applied to the actor).
    
    For useractors, this normally occurs when ifhitweapon is called.
    
    Set RETURN to a nonzero value to skip applying the damage. This
    will also cause the 'ifhitweapon' conditional to skip the branch.
    Note that doing so will not automatically reset htextra to 0.

commit 2e5741cc4f4a7a757decabd2c92f229762d72bf0
Author: Dino Bollinger <dino.bollinger@gmail.com>
Date:   Thu Apr 28 16:15:37 2022 +0200

    Duke3D: Add global gameflag "DUKE3D_GLOBAL_ADDITIVE_HITRADIUS"
    
    If this flag is set, all radius damage sources will apply cumulative
    damage instead of overriding the existing accumulated damage.
    
    Equivalent to applying PROJECTILE_HITRADIUS_ADDITIVE to all explosions.

commit 3c4a8bb417631f740bd147679db3e894c8254ed9
Author: Dino Bollinger <dino.bollinger@gmail.com>
Date:   Fri Nov 19 23:56:27 2021 +0100

    Duke3D: Add projectile WORKSLIKE flag PROJECTILE_HITRADIUS_ADDITIVE
    
    This flag alters the radiusdamage calculation such that the blast
    damage is added to the current htextra of the actor, rather than
    overwriting the current applied damage completely.

See https://voidpoint.io/terminx/eduke32 for more details.