This is a variant I made up for playing an altered versión of risk trying to get an X-COM vibe. Check it out and let me know what you think.
Risk XCOM: Enemy all over
Invasion Force Replenishment:
The aliens get 10 aliens per round split by a 1d10 and placed by selecting cards from the continent where the ship is docked, plus any extra amount of aliens due to stars.
When replenishing, if the space dictated by the card is occupied by human forces a battle ensues immediately.
Invasion forces will replenish until the humans destroy the spaceship by taking it over. They can only board the ship from the space where the ship docks.
The aliens only move towards adjacent spaces that contain fewer enemies than the amount of aliens of the departing space.
Defending Force Replenishment:
Depends on the amount of territory controlled by humans the same as per normal rules plus the reinforcement star bonus of selecting one card at random.
Same rules apply as in regular risk.
1. If the aliens eliminate all human forces.
2. If the humans destroy the alien ship and eliminate all aliens on the map.