How do these two interact when using Perplex to lower a value? Say a character has a printed damage value of 5. Power Dampening Field says it's now a 3.

If I Perplex the value down three times, does it become a 2? Or does it become a 0?

prior to the newest rules it was pointless.
you'd modify to 4, and then when it was used power dampening field makes it 3.
New rules- replace then modify check when its used, so
replace 5 with 3, then modify 3 by -1 to 2.

so this is actually a surprisingly good tactic for a DR team.

This right now is my "Contingency Plan: Galactus" strategy. I'm possibly playing in a 700 point game this weekend and, if anyone shows up with a Galactus, I want to pummel him into the dirt. Malice and Barrier and Structural Integrity Field are also there to deal with one Galactus, but I'd like to have multiple options for dealing with him (or dealing with multiple Galactuses).

I'll probably show up with another, friendlier team if no one comes with Galactus, but I want to hammer that overcheesed piece like a carpenter with a nail should he rear his big, purple head.

It would seem to me that you can modify down. Anyone, no matter what their damage value is, for all purposes has a damage of 3. Don't see why you wouldn't be able to perplex down from there. But, hey, what if they play ordinary day? Then your team could be in trouble.

Theme team. That won't stop two Ordinary Days, but I should have one auto-win against Galactus otherwise.

Not exactly a fun way to play, but anyone playing Galactus really shouldn't expect someone to play a fun team against him.

Nice. I wasn't thinking theme team with such a high point total. And I agree, what's the point of playing galactus. Either you win, in which case you've merely done what's expected of you, or you lose and feel like a complete failure for losing with galactus. Not much entertainment either way.

Keep in mind that Structural Integrity Field will no longer have any effect on those Barrier tokens.

Ah ha! Forgot about that! So Power Dampening Field it is!