Traveling Through the Apocalypse, I Can Actually Become an Immortal

Li Feng traveled to the end of the world, and the system unlocked the function of cultivating immortals! ? Zombies are rampant in the apocalypse, humans work together to light up the technology tree, and mechas and zombies fight! ! How to do this? How can I cultivate immortality when my spiritual energy is thin? And that zombie, can it be upgraded? ! Is the mecha nuclear powered? I want spiritual energy! I want to improve my cultivation and save my life This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.