I recently did a review of just what happened during the asteroid/comet impact and afterward, and it was insanely bad. And not limited to near the impact site,

I recently did a review of just what happened during the asteroid/comet impact and afterward, and it was insanely bad. And not limited to near the impact site, either, as ejecta shot back into space and rained down on the whole planet. The atmospheric temperature was well above boiling, rain of fiery stones starting literally all the world’s forests on fire, earthquakes of 11 on the Richter scale. For those within visual distance of the impactor, flesh would turn to flame due to the intensity of the light. Massive inland tsunamis. Followed by years and decades of dark winter (50 degrees below average) and then 5 deg C global warming for thousands of years. Almost everything would’ve been dead on land within hours. That species survived means a few individuals survived. Something like 99% of everything living on land would’ve been killed early on. No exclusively land-based tetrapods over 25 kilograms survived.