I know nothing about this game is it like homeworld or more like a master of Orion type game
Planet micromanagement is reduced to a bare minimum (just just give high-level decisions - like population managment, terraforming/infrastructure ratio, overharvesting, stations and platforms in orbit, trade, etc..- you don't order buildings built on planets). Strategical map is in 3D (there are 3D maps for those who have trouble with it).
The battle itself is somewhat like homeworld, but commands are limited to a 2D plane (altough ships will go above and below if necessary - when chasing or running from an enemy - you just can't give a direct "move up order").
There is full Newtonian physics at play, so ships mass, acceleration and kinetic impact of enemy weapons all have an effect. Specific ship sections and turrets (actually, specific polygons) can be targeted and hits are calculated in real time (a shot bouncing off a curved hull depending on the type of bullet, speed and angle)
Ships are created from mix-and-matching 3 sections (which have different fire arcs, number of guns and other options) and equipping them with weaponry and additional stuff, like reflective coating or extra armor.
There are 8 races (I'm counting the two expansions), and each race plays and feels compeltely different.
Both on a tactical and and especially strategic level, they are VERY different.
Also, NGTM-1R's observations are either false or obsolete (expansions rock).
Getting the biggest hull first is not the road to victory (altough DN hulls are powerful), there are plenty of tactics and techs to counter bigger hulls. Bio-Warfare only works if you can come in undetected (BioWar sections are fragile) and the enemy has practicly no point defense or you can tie it up somehow.
Attrition works as a tactic, but so does blitzkrieg and morale wars (yes, you can make the enemy empire crumble by sabotaging their morale).
Diplomacy is light, but it's there. The AI players play to win and act upon what they know (which is limited, they don't cheat in that regard), and different races will act differently.
If you are stronger and want a enemy to surrender, a good idea would be to research their language Xenotech tree and send them information on your empire (colonies). Once they see you are bigger, they might surrender.
If they refuse, you can go from planet to planet and demand planetary surrender. The AI isn't stupid, so it will usually surrender once it sees it has no chance. All in all, one of the best AI's out there.
You can't directly trade tech, but if you can start special research projects that will give your ally a specific tech they missed. They still have to research it after it appears on their tech tree.
All in all, it's focused on glorious battles and high-level decisions, instead of micromanagment hell. It also plays fast enough that it's fun in multiplayer too.
Personally, the best 4X game I played.