So what do I mean by "Hard Science Fiction"?

Probably not as hard as you're hoping!

I mean I will try to make sure that the science in the game has some kind of plausible
theoretical basis in reality, and that I want to be corrected if I make any mistakes.
If I have to go against any current science, I want it to be an informed decision.
For example, because time needs to run at the same speed for all players in the game,
I am probably going to have to add some way to travel faster than the speed of light.

So basically, as few hand-wavey things as possible, with the rest rigorously explained.

If you're an expert on a field I've made a mistake in, PLEASE let me know!

/ Notch