MEGApack update.

The number of creatures should be increased to 20, so that more neutral creatures can be included. The neutral creature upgrades themselves are not bad, but often they make upgrades to wolves, mummies, or phoenixes, which negatively affects the original game. Also, the idea of upgrades is flawed because they create a weaker creature (compared to the unupgraded version). Furthermore, I've seen attempts to add entire city replacements with 21 creatures, which is also not ideal. And sometimes you want to take only one creature, not all three – you simply don't like them – but then there are possible side effects, such as the file requiring a non-existent creature for the upgrade, and something needs to be done about this to prevent the game from crashing or ignoring the file. In the end, it's often easier not to take any creatures at all to avoid this hassle. These kinds of manipulations (and unnecessary dependencies on other creatures) make them unattractive.