The nice thing about doing science on the moon is that it's safe there. No matter how mad the experiment gets, there's about two hundred and forty thousand miles between the two planetary bodies and it's all hard vacuum and radiation. It couldn't be any safer or more quarantined while still being within reasonable distance of radio communication back to home base. Even a ravenous biomass of iron-consuming fury would think twice about covering that kind of distance, if only due to the travel time giving Earth forces plenty of advance notice to nuke it into oblivion. If there was something like a stargate up there making transport to the home planet trivial, that would just be incredibly poor planning.
So anyway, there's a giant interdimensional mutant biomass overrunning the planet by turning its machines into half-steel, half meat monstrosities. All of Earth's armies are helpless in the face of the bloody carnage so a team of heroes rises up to splatter biomech parts wherever they're found. Iron Meat is a run and gun pixel-art side-scrolling shooter in classic Contra style, filled with guns and gore in the best 16-bit tradition. Granted, the SNES and Genesis would have choked...
