[Varyon]

With the sheer quantity of HP characters tend to have in such games, and the fact it’s not uncommon for HP to scale linearly with level, IT:DR is often the way to go. Of course, you often don’t need much scaling if trying to emulate a lot of modern video games, as enemies usually scale with level, meaning a fight with a soldier at level 1 and one with a soldier at level 99 is often only different in terms of options available and that each hit now averages 500 damage instead of 5 (but as the soldier now has 3000 HP instead of 30, he drops just as quickly).

DnD is typically different, as outside of certain spells damage doesn’t scale as quickly as HP, so high level combats usually last longer if they’re slugfests.

The real question, of course, is what kind of feel you want for your setting. If you want something where an arrow to the chest is a Big Deal regardless of how badass you are, GURPS default can work well. If you want Big Damn Heroes to shrug off such wounds, increased HP or IT:DR is probably the best way to go. If you want characters to be able to basically soak a lot of damage but then end up roughly as fragile as a normal human once this is depleted, Ablative DR or Vitality Reserve (see the previously-linked Krommpost for a rundown of the pros and cons of each) is the way to go.

For reference, the above are roughly appropriate for things like Goblin Slayer, the Marvel Cinematic Universe, and RWBY (speaking of arrows to the chest...), respectively.

Edit: Does Force Field actually protect against the Blood Agent Enhancement? That seems like it would be stepping on the toes of Sealed a bit too much (also, the same justification could be used to allow it to work against Contact Agent, which seems rather excessive to me).