A total number of animals has not been released, but the pack already surpasses all other user expansion packs in number of animals. Originally, remakes of five of the twelve Zoo Tycoon dinosaurs were to be included, but they were cut from the pack shortly after the announcement of Radical Remake.
Cretaceous Calamity will be the first user-made expansion to include functional maps. Unlike saved games, which must be installed to a player's profile, these will function as official base maps for Freeform and Challenge games. Maps to be included are as follows:
The wait for Cretaceous Calamity has been highly anticipated among the Zoo Tycoon fanbase. Mysterious Map Marvels once released a weekly picture (dubbed "CC Mondays" as a reference to the "EA Wednesdays" Blue Fang Games did) or a 360° spin video with a voiceover showcasing a particular animal and its features, which can be seen on YouTube (right). These were usually accompanied with a poem that allowed fans to guess what the next animal was before revealing. Unfortunately, Mysterious Map Marvels no longer does "CC Mondays", though they still update periodically. Amazingly, the Zoo Tycoon Volcano page for Cretaceous Calamity is over 267 pages long. However, it had been locked in an effort to stop spammers and such from spamming up the thread. But the topic was reopened by MMM member King Hoopla.
An incomplete and unfinished version of Cretaceous Calamity was leaked online, and MMM members Incinerox and JVM spearheaded against them, recommending members do not download the leaks. However, they moved quite far around the community, prospering especially at Caldera Unlimited. Waves of criticism were aimed at MMM over the unfinished content, including issues with the size of the animals, and JVM mistakenly reportedCretaceous Calamity was cancelled before Incinerox declared it was only on hold. Leaks continued and eventually spread to YouTube with legocreator5000 becoming particularly infamous for these activities, forcing MMM to reveal they had been working in secret for months in an attempt to stop it. MMM experienced direct criticism from several members of the community for these efforts, and JVM left Mysterious Map Marvels as a result shortly after CC's continuation was announced publicly. He left the community soon afterward. Legocreator5000 then apologized.