"Falsifiable" has more than one meaning; in regards to scientific theory, it means:

Adj. 1. falsifiable - capable of being tested (verified or falsified) by experiment or observation.

If a theory is not falsifiable (i.e., if it cannot be proven either true or false) it is useless. Steve Kirsch is saying that at least one event featured in the film can be proven false. See below for more.

Here is Dr. Robert Malone's comment on one of his concerns about the film: https://rwmalonemd.substack.com/p/sins-of-information-warfare

This is directly analogous to one of the apparent breaches of accuracy in the current “Died Suddenly” video, wherein (apparently) an example of sudden death is being used which is demonstrably unrelated to SARS-CoV-2 (COVID) vaccination. It may or may not even be the same event.

My opinion is that these breaches of technical accuracy are not acceptable. For either side of the debate. It is often said, when debating an opponent (or an internet troll) that “you are entitled to your own opinion, but not to your own facts”. Furthermore, these types of “artistic license” distortions of truth cause both damage to the credibility of the arguments being made (which may otherwise be valid), and can also cause psychologic pain.

Furthermore, these types of errors become weapons which will be deployed against us by our opponents in this unrestricted information war battlefield.

Comment by an anon ("A Midwestern Doctor") https://amidwesterndoctor.substack.com/p/what-is-causing-the-died-suddenly

(This is a long piece about "vax" damage; the Died Suddenly film is a very small part of the discussion):

Unfortunately, as alluded to above, there is one huge issue with this segment. The live clot at the end has nothing to do with the COVID-19 vaccinations (it came from a surgery posted on youtube a year before the vaccines entered the market). I suspect this arose because someone re-uploaded that clip and labeled it as being from the vaccines (either as a prank or as clickbait) and then it was re-shared until the Died Suddenly team got it and added it in since it supported their narrative. This illustrates why it is so important to have strict editorial controls on any production, especially one that is difficult to revise after the fact and will be viewed by large numbers of people. I debated clipping that ending part off (since it makes this a much worse clip to share), but did not as I felt it is important for our community to be transparent and open about any inaccuracies on our end.

Later, he adds:

The producers of Died Suddenly have my genuine sympathy for these oversights, as I recognize from writing here on complex subjects how easy it is despite my best efforts to make factual errors and as much as I hate to say this “spread misinformation” (this is why I and colleagues periodically volunteer to vet medical information being compiled to challenge this vaccination program).

At the same time however, I also believe once these mistakes are recognized, they need to be addressed. Since I can edit my own written posts after publication, I recognize it is much easier for someone like me to do that than a video publisher, but I nonetheless believe it must also be seriously considered for a documentary that had a limited release to a video-sharing platform.