Very cool concept! My feedback:

Art

I like the unified and simple art style, nicely done making it cohesive. 

Bugs

When I died at the end, a menu appeared asking to retry or give up. I clicked restart and it crashed or something; the game became unresponsive and I couldn't continue. 

Controls

It would be nice if shooting would continue on a timer when you hold the mouse button rather than clicking for each shot. 

Game Design

I really like the design of the cargo units but I felt the "spread" shot wasn't worth it at all... until suddenly I was overrun and could have definitely used it lol. 

I love the concept of the this game! I did eventually get off railed somehow, and I had to watch as everything I worked for floated off into the void 😅but other than that, I enjoyed it!