That's a big map man. From the level design, that's amazing.
Visually - and when it comes to the use of assets - 5 stars.
However, the take on the theme isn't that much clear (except for alien symbiosis in the flora of the map) and gameplay mechanics aren't tied much to the theme. It was frustrating when i died a couple times and I was at the start with no checkpoints, there is no life system too. Audio is fine, just needs some polish here and there.
Good job, this submission was a lot of work.