RTF is a global modification that replaces all towns in the game.

I also thought about a steam tank, but I came to the conclusion that it wouldn't work for Heroes due to the unit size limit – a tank would need at least a driver, gunner, and mechanic, so they wouldn't fit on a 4-cell space, unless the steam tank is turned into a steam tower (by the way, that's an interesting idea).
I wanted to make a Yeti out of the monsters from Might and Magic VII and put it on the seventh level.