Brock Boeser, Travis Hamonic and Tyler Myers each had a goal and an assist for the Canucks (23-28-4), who have a three-game point streak (2-0-1).
It was expected to be the final start for Demko in his first season as a No. 1 goalie.
"I'm pretty happy with it," he said of his season. "It's been a crazy year, definitely the hardest year I've had to go through, just unforeseen adversity, having to battle through a bunch of stuff. I speak for myself and I'm sure some of the other guys in the room, but I feel like I'm a stronger hockey player coming out of it. If we can make it through a year like this, we can probably make it through just about anything. Trying to shine a positive light on the situation and learn and grow from it."
Louis Domingue made 20 saves for the Flames (25-27-3), who had their three-game winning streak end. He last played in the NHL on March 1, 2020, when he was with the Canucks.
"It felt pretty good, pretty special," said Domingue, who played three games in the American Hockey League but spent most of this season on the taxi squad. "Sometimes you go through things in your career, like in my case I probably didn't think I might not even play another NHL game, so pretty privileged."
Neither team qualified for the Stanley Cup Playoffs. It was the second of three straight games between the teams to finish the season; the Flames won 6-5 in overtime here on Sunday. The teams play each other at Calgary on Wednesday (3:30 p.m. ET; ESPN+, SNW, SNP, NHL.TV).
"You're looking at, or giving some players opportunities they normally wouldn't get to raise their profile a little bit," Flames coach Darryl Sutter said. "So that's what you're still looking for is how they prepare and how they perform."