Thanks for playing and really appreciate the feedback!
I absolutely agree with your points about the rate of progression and clarity of numbers. They're the first things I'd work on if I dedicate more time to this. (It was made for a course, on a deadline, so of course some things just aren't as polished as I'd like!)
And thanks for pointing out that Lorentz factor error. I was aware it's dimensionless, but carelessly copy pasted some code and forgot to remove the unit! Will certainly at least fix that.