Massive beasts live in this dam planet! And you never know where they are... So be prepared for war! I strongly recommend you to invest a lot in military strength. If they come, and you are not prepared, it is better your Rocket is ready to leave the planet!
This mod adds some heavy challenges to your game:
-attacks from enemy groups of human soldiers, heavily armed
-huge biters (many types, each one with its own special effects and weakness)
-Ridiculous Great Worms attacks! (you don´t want to know)
-A destructive volcano that will erupt and burn things around
-The evil spidertron!
Note: It is serious! You must have all kind of damages to deal with these monsters (fisical, explosion, pierce, laser, fire)! They have many resistances and only one weakness. Consider adding some mod to help with military strength, like bobs warfare. And call your friends to help in a multiplayer game (more players, more dificult, more fun).
Difficulty scales automatically based on evolution and number of players.
Check mod options for setting attack intervals, chances, etc...
Check the mod in action, on the great Adventures of Coyote!
And there is a review from JD-Plays on his Factorio Mod Highlight