I've started to implement FAINT animation to all players, which plays when the player has low HP. To give more emphasis to the effect, the character will blink in red in alternate frames.

Here are some examples (ignore the strange colors, its the smartpal in action) I did manually in Photoshop:

BRAND

(Brand looks she is very pissed off, lol)

EMMA FROST

(Since she doesn't have a faint animation - she morphs into Diamond Form automatically when has low life, this is her new idle while in Diamond Mode too)

HULK

CAPTAIN AMERICA

HAWKEYE