The first step is to modeling, texturing and modeling
the second is to fing the property of each aliens, humans and builds.
Add the alien or weapon one by one is the worst solution
because, I create an alien, this alien is adapted to the original aliens and weapons
now I create a new weapon, it have to be adapted to the original aliens and to the new alien I have just add.
Now I create a new build who it have to be adapted to the original and to the new alien and weapon I have created.
As result it become a Puzzle!
All of this for say the king is going to be necessary against the ram, the mabooner and the queen !
And the size is not a problem, it just have to be change.