There was embarrassing writing, embarrassing acting, and listening to Amber Heard trying to deliver this terrible dialogue with zero inflection was exhausting. Why does half of the population of Atlantis sound like they're from California? The dialogue was never more than cliche with a predictable plot. The "advanced ancient civilization hidden away from the world" trope is already old. There was so much CGI that none of the action ever felt impressive or tense or real. Any time someone said "Ocean Master" with a straight face I wanted to laugh.
This would've been the perfect movie to not take itself too seriously, go for a more lighthearted and irreverent tone like Thor Ragnarok, but they just try so hard. It has none of the superhero charm that Marvel manages to carry over from the comics and thus you have one very long boring slog.
How many scenes did we need where a quiet moment was interrupted by an exploding wall that didn't hurt anybody? I counted three or four. Also, that paint-by-numbers forced romance - "Wow there was a surprise and now we're accidentally holding hands", "Wow there was an explosion or something and I grabbed you " - give me a break. And whoever put together the soundtrack for this film should be summarily executed.
