Its weapons seem weak. No beam weapons at all. The following assumes this will be a space armor, as you put sublight speeds in.
(1): The UMD's black slug will be invisible to certain types of sensors, but you can still see it. Just so you know. Also, the only useful shell, the antimatter one, is hampered by the fact the round has no speed attached to it. It won't be very useful unless at extremely close ranges.
Also, the revolving chamber seems off. You want it to be like a revolver, right? If so, you cannot have a round in the chamber (revolving cylinder is the chamber) unless you create some kind of loading and extracting mechanism for the casing, if it uses a casing.
Even if it doesn't, you need to specify how that first charge in the barrel (combat load?) is fired without firing the charge immediately behind it in the chamber.
(2) Dart Launcher: This sounds cool. Kind of a mini-missile launcher of sorts. But again, very little damage.
(3) Vulcan gun: This isn't going to hurt many spacefaring craft. I assume that's not the point, but still.
(4) Chainsword: This seems very ... funny. But not necessarily useful; if you're swinging this baby in space, chances are you'll only get a glancing hit unless this thing is cycling at HYPERSONIC speeds. Vibroblades are better than saw weapons for this reason. You'd have to really grind on a target to even start to damage it.
I'm not saying the tech's bad; it all seems really good -- for aerospace warfare. But beyond that, this thing's a sitting duck to all but the Demon. Good defense, insufficient weapons.