For his trait smash well developed sense of irony, it doesn't specify he counters powers until when. So are all powers countered until the end of the game? And are ALL powers countered, even those who are not appearing on the dial at the time the power activates?

They updated this power when the new rules came out.

SMASH WELL-DEVELOPED SENSE OF IRONY!: When Hulkpool hits a single opposing character with a close attack and his attack total is at least 4 greater than the target's defense value, after resolutions choose one: heal Hulkpool 3 clicks, or the target can’t use powers until your next turn.