It started slow, and continued to largely be slow. It had moments that tried to shine. I've noticed a lot of South Korean films like to shoehorn in Americans as villains. Buuuut after 2 years of a pandemic the villainous Americans handled it closer to real life apparently.
Even ignoring that, its a film that could have been cut in half and lost literally nothing. How it has a 6.6 average score is beyond me. If you want a "Virus outbreak" film that is actually good and worth the time, watch Outbreak with Dustin Hoffman or The Andromeda Strain.