Gene-Tech: Before the Storm

Gene-Tech: Before the Storm is a single-level PK3 for GZDoom. It was made by Nigel Rowand (Enjay) and released in September 2014.

This WAD is notable for only using 3D models and no sprites. It includes enemies and weapons from  and was designed as a prequel to the events of that game.

Plot
The player is a Global Defence Force (GDF) soldier tasked with infiltrating the Gene-Tech corporation, a company based on Mars that specializes in genetic manipulation and cybernetic integration and is believed to be working on new technology alongside an alien race. The GDF considers this work to be a security risk, so the soldier is instructed to discover the nature of Gene-Tech's work and neutralize any alien threat that exists by any means necessary.

As the soldier penetrates deeper into the facility, they come under attack from alien soldiers that emerge from black hole generators. The soldier then learns that Gene-Tech have been working with the Strogg to acquire better technology than their competitors; the Strogg, meanwhile, have been studying how to combine their technology with human biology - having succeeded, they are using the Mars base as a staging point to invade the rest of the solar system. After defeating a heavily-armored "tank boss", the soldier leaves the base by dropship just as the invasion begins proper.