It started like any other day, people going about their business hardly noticing their fellow citizens, or what's going on beneath their feet. Deep underground mad scientists are raising monsters from the planet Moongha. Once fully formed they will emerge to spread terror and destruction. Cities will be laid waste to, and the human race will be hunted to extinction.

Through the sewers oozes the Bloob, quietly growing in size. The Drakoor, alien vampires, stalk the night feeding off the unwary. Meanwhile, the strongest of the Moongha invaders, Mechoor, sucks in energy from the earth. Once sated it will rise to destroy whole cities with its heat ray. These are just a few of the monsters that will terrorise the people of Earth.

It can only be hoped, that just as in the moves, there is a hero around who can thwart their evil plans, otherwise there will be no more 'just another day' for anybody! But who's behind those evil plans? You!

You are one of those sadistic, power-thirsty, pyscho-nerds, eager for revenge after years of abuse from colleagues who, rightly, thought you were crazy. With help from alien technology gifted to you by a mysterious benefactor you are ready to take your place in history!

Moongha Invaders is for three to four players and should take around ninety minutes to play. The game will last either eight or nine turns, depending on the number of players. It may end before then if a player manages to get all twenty of his rubble pieces on to the board.

You have control of a number of different types of monster and you use the side of the board closest to you to track their status and health.

At the start of each turn a random number of actions are made available. Three of these actions relate to your monsters, allowing you to create, move and attack with them. There are two human related actions, allowing the placement of heroes and military units.

You create your monsters by acquiring orange tokens. Once you have enough you place your monster on the board. However, at first it remains unnoticed by the humans and so a 'Hidden' counter is used to mark its position. While hidden a monster is safe from the military and other monsters, allowing it to build up its strength to launch a massive attack. Other players can attempt to discover your hidden monsters with heroes.

Only three monsters are powerful enough to damage cities, which are the Bloob, Moogre, and Mechoor. When you attack a city with one of these monsters you place rubble pieces to mark the amount of damage you have inflicted.

Your monster will become revealed if it attacks or is discovered by a hero, at which point it can be attacked by military units, such as infantry and armour.

At the end of the game you will score points depending on how many rubble pieces you have in each city. You also score additional points for certain cities that were secretly allocated to you at the beginning of the game, depending on how much damage they have received. You may also score points for having Drakoor pieces on the board and for having killed other monsters with your Moogre.