The parts that stuck with me most were energy management and the whole "feel" of "this is my ship". I love the way you can assign energy levels, turn items on or off, overload items, expend or recharge onboard battery, all of that! A lot of my writing has become more concerned with energy management and reactor sizes - namely that most ships I write about are too small to mount a proper reactor, so they use large capacitors and survive a short battle on battery. The expanded mechanics on "you can fire one weapon normally or two weapons at 75% speed for 30 seconds" has spurned a lot of thought for me into thermal management, as you can image that an overloaded weapon would be prone to overheating.
That said, it's not hard sci-fi, and for the most part I don't write hard sci-fi either. Aurora (designed by Pentarch) does much more hard sci-fi with missile encounters at 50 million km range. But it offers no graphics, understandably, as there would be nothing to see. The ship you're aiming at is so far away as to be invisible, at the edge of your long-range sensors while the minimum weapon range is some 10 km. It's grand in design and thought, but it's not theatrical. Nexus aims to be theatrical, and that only happens within about a 10 mile radius. It's simply one of those things where you have to sacrifice realism in favor of entertainment. 3 month trips from Earth to Mars is boring. 15 minute battleship brawls are considerably less boring. And the sheer joy of watching a railgun impact shatter an enemy's hull is just satisfying.