San Francisco, 2021. The first one was spotted. A large beast, at least 700 feet tall. Huge. Slow. Gigantic. It destroyed everything. More of them started appearing, every one different. All over the globe. No purpose. They came out of large cracks in the ground after earthquakes. Well call them the Beasts. Then, the international group ETAL. Eliminating The Alien Threat. Many efforts were tried. Robots, weapons, nuclear bombs. Nothing. After years of intense genetic engineering and research, a working idea was invented. Project ReCreature was created. Using a new technological discovery, a few select participants will gain the ability to transform into monster-like beasts. They must defeat the threat. You must defeat the threat. Travel into their world and kill them off, once and for all.
Where the creatures are from, it's strange. There are multiple biomes that are separated by seemingly nothing. If you're in one, and you walk long enough, you'll reach the other even when there was no end or door in sight. From jungles, caves, and lava-filled hells, the Beasts prowl there. You must destroy them and survive.