I've played the alpha quite a bit, will attempt to simply illuminate facts, not have an opinion.
Exploration - Pretty conventional, but there's not a lot you can do here. It is worth noting that there is no fuel or range limitations on ships, they just get faster at you tech up. It is entirely possible to explore the entire galaxy with the starting scout ship. Similarly, once you visit a system, you know who owns it, which planets are colonized, and so on. Sensors seem to be used primarily to keep on the lookout for ships.This is one of the parts of the game I have to figure is still unfinished.
Expansion - Again, nothing new here, but that's part of the charm. You build colony ships, fly them to a system, and press a button. There is a large range of tech on colonizing different types of planets, and little in-game achievements if you're the first one to colonize a particularly hazardous type of planet. Something worth noting is that beyond the wide variety of planetary traits and resources. The basic resource system is built around Food, Industry, Dust (money) and Science (abbreviated in-game as FIDS). Each planet can be specialized in one of those resources. Additionally, each planet can have a number of traits (like 'Deserted Cities' or 'Hollow Planet' or 'High Gravity') or something and additional Strategic or Luxury resources, which effect the development of not just the system but also are required for certain developments.
Exploitation - Besides the above resources, there's also managing developments. It took me a bit to realize that not all developments were worthwhile in every system. For example, a development that gives a food bonus to explored moons doesn't make much sense if none of your planets have any moons. While it's nice to see try and make people weigh the positives and negatives, it falls flat a bit. Developments only ever cost money to maintain, and in the time I've played I've never even run remotely short of cash (unless I'm rush-producing battleships). Similarly, there's no cost to colonize a new system (beyond the money and 1 unit of population necessary to make a colony ship) so the early game tends to be a mad rush to grab every system you can before the others guys do. The AI seems to do a poor job of managing its colonies, but they never seem to be low on cash or something. All in all, there's not a lot of challenge or deep management in the whole development aspect. It works well though, so I'll chalk it up to the game being unfinished.
Extermination - My first impression of the combat was that it was like GalCiv's 2, which made me sad. Then I started actually getting into fights, and I got happy. The basic run of it is that there's three weapon systems, Guns, Lasers, and Missiles, and three corresponding defense systems (shields, differentshields, and flak, or something). But it changes slightyl with the way combat works. When two fleets encounter each other you go into combat mode, which is divided into five stages. Arrival, Long-Range, Medium-Range, Melee Range, Resolution. As the ships arrive, the player has the option to select three cards one for each combat phase. Each card is designated in a certain way (Offensive, Defensive, Engineering, Sabotage, etc.) and has some effect, either on your ships (+40% Defense against Beams, -20% Kinetic Weapon Effectiveness) or on the enemy ships (Enemy Ships -15% Accuracy). It's a decently varied selection. Whether or not the card goes through depends on the type of card played by your enemy. It's like rock-paper scissors, sort of. Engineering cancels out Sabotage, Offensive beats Engineering, and so on. So the trick becomes to play cards that benefit you AND will hopefully cancel out what the enemy is using. Against the AI it's sort of a toss-up, they'll use cards of no practical use to them (a Missile Booster when all they have are guns, for example) ad seem to be rather uncanny about picking just the right card to beat you.
Other than picking the cards you just watch the ships shoot at each other. It plays out like ye olde Line of Battle affair with sailing ships. I happen to think it's pretty neat. At present it could use with some camera and speed controls, but I assume those will come later.
So in summary: For supposedly being an Alpha, a very solid, polished, and reasonably entertaining, if not terribly innovative (but then, don't we just want a remake of hte classics at this point?) 4x.
and apparently it will also feature real time combat. Guess the decision has been made for me 
