I hadn't heard of LUMENDARK before, but this makes me want to read it! I really like the monster designs. They feel both alien and threatening. And the encounters progress quite smoothly, a simple encounter followed by a veteran followed by an epic boss fight. This scenario looks easy to pick up and run.
A few critiques:
I'd like a little more detail on the planet itself. It's clearly capable of supporting life, which creates an odd tension with the damaged life support and its associated penalties. I assume the air isn't breathable and the water isn't safe to drink? If so this could be made explicit.
I also think it would be easy for the adventure to go off the rails. I can imagine players trying to repair the life support and propulsion systems before going scavenging. Some players may not think they'd be able to find repair parts for the ship out in the brush unless explicitly told, and may stay put trying to repair the ship with what they already have (especially given how hostile the fauna are).
Overall, great work!