Well done building something so engaging with so few assets! Nicely polished as well.
For me, gameplay was too difficult. First go I unlocked everything as quickly as possible and had no idea what was happening. Second time around I took my time and did better, but still had too much stuff happening to really understand what was going on. It may be easier if some modules could just be "completed" at some point, so you have fewer things to worry around. E.g. an option to weld the damn airlock shut after closing it for the five hundredth time. There would still be escalating difficulty as the modules get more complicated, but it would make the end more manageable for the average player I think.