Sorry, thought most people would be using an intermediate program to modify and select how they wish to print. I think some want to print a ton of parts separate by color in which I don't have the robot arms etc boolean cut to shape around the ship to be glued later. They all are intersecting parts.
Take a look at the new files "FooParts". Gun, Alien, Ship are all 3 separate parts that you should be able to feed how you guys are loading. I ran them into Cura to make sure they would slice properly. They look fine to me and already printed the alien so I know that's a good file.
If an object is ever that small, usually a scaling conversion from inches to mm (25.4mm per inch), so scale by 2540%. The gun has some steep edges on the barrel + grip with those grooves so you will likely need supports or it will have to modify so its angled less, but is going to ruin the shape. Since I don't have the game, I don't know the true scale of the actual molded part, so you may all need to scale at your own judgement, but the alien scaled up how I said makes him about the width of a pinball so it looks pretty close to whats in the game(?)
Let me know if you still got issues, hopefully it gets good use. Also the gun hasn't been tested for print fitting either. I did a wider boolean cut so hopefully the grip and barrel can be fit glued right on to the base. Gun doesn't replicate any real world game part, so if scale as you will for whatever/wherever you want to print it for.