The Tigers emerged from a flat night at the KC Stadium with a 1-0 win and a place in the last 16 for the first time in 36 years.
German striker Nick Proschwitz grabbed the winner, powering George Boyd's cross home from inside the area for his first senior goal of the campaign.
But on a night where both sides rang the changes - Hull making nine alterations and Huddersfield weighing in with 10 of their own - Bruce was hardly in celebratory mood.
"It was a comfortable evening for us but it was, if I'm being honest, like watching paint dry," he said.
"There was no real cohesion to us, it was both managers throwing 11 bodies on the pitch really.
"Once you lose that cohesion there was no real tempo to it because of what it was. It was more like a friendly that a cup tie.
"But that's what the early rounds of the cup have turned into now; it's a shame but there you have it."
Bruce, grasping for the odd positive though clearly less than enamoured about a night that attracted little more than 7,000 to the KC Stadium, offered: "The good things were that Gedo got a run out and Stephen Quinn got another hour under his belt after being out for a long time.
"Abdoulaye Faye and Alex (Bruce) needed a game and Steve Harper did fine in goal.
"We were a bit unbalanced but it was a question of giving everyone a game."
Terriers boss Mark Robins took a more positive stance on the match.
Although a congested fixture schedule - Huddersfield are in action again on Friday against Blackpool - meant a full team was never in his mind, he believes there is value in the competition.
"It wasn't a brilliant spectacle I don't suppose. But this is a really good cup competition and an important one, make no mistake," he said.
"I wanted to go through, but needs must. It (the team selection) is no disrespect to the cup - it's a necessity.
"Our priority is staying in the Championship. We have two games in a very short space of time...we recover on Wednesday, prepare on Thursday and play again on Friday.
"I'm disappointed. I wanted to win and we might have won if we'd been at our best.
"But history tells me that this team was the right way to go, even with the risk of not qualifying for the next round."