I have always enjoyed the Sci Fi game of OGRE by Steve Jackson. Ever since it first came out (along with the companion/expansion game G.E.V) as a small budget price game contained in a box not much larger than a smart phone it has followed me around.
For those that are unfamiliar with OGRE it is a very simple game in which the basic, classic scenario pits a single OGRE against a variety of opposition unit types. The victory conditions are very simple - the OGRE player has to destroy the enemy command post whilst the defenders have to stop the OGRE.
The OGRE is a self aware cyber tank armed like a battleship and able to engage multiple targets. The defenders have an array of power armoured infantry, heavy tanks, missile tanks, howitzers and G.E.V.
There have been a number of versions of the game and also some miniatures rules to support the metal models that were available to support them. These now command some high prices and so when Steve Jackson games launched a kick starter project to release the models in plastic I was highly delighted. I did not take part in the kick start project (I did not need to as it was funded very early on) but have finally gotten around to acquiring a set of the miniatures - and very nice they are indeed!