I had to buy this game again in order to review it. My hours played does not include the older Steam version that isn't sold anymore.
This is hands down my favourite game of all time. Therefore I am actually going to take time writing this review.
Ridiculously deep, engaging gameplay that can allow for 250+ hours for a single large game - a game filled with desperate struggles against merciless and highly adaptable AI in long late-night/early morning sessions. A very nice physics engine allows for some interesting RTS battles with completely customised ships bristling with esoteric weaponry - from the humble red laser to giant space revolvers that shoot asteroids that glass planets.
With a quasi-randomised tech tree system and 6 different races that each play completely differently, it is easy to spend thousands of hours on this game and still not experience everything it has to offer. Multiplayer is just as good - coordinate with a friend or compete against them in 4X/RTT combined gameplay. If you thought multiplayer games of Sins of a Solar Empire or Civ were long, this game is somewhat longer, but rewards you with deep satisfaction during and after play.
Overall it is similar to the Master of Orion series of games if you remember those, but also feels akin to Total War with the RTT combined with turn-based strategy, and the depth of control available during battles. Most of the time you are trying to expand, tech up and survive in a turn-based 4X type strategic map.
However, if one of your ships encounters something hostile, you are given the option to fight manually; this is often very rewarding, you are able to visually assess the ships, including tech level and weaponry, and to also destroy them with extreme prejudice (or not if you prefer). The RTT game engine allows polygon targeting, allowing you to aim shots at precise parts of their ships - snipe off their turrets or shoot out their engines so their inertia causes them to crash into a planet. The level of detail simulated allows for incredibly fun and often unpredictable fights. This is not like Sins, where ships have simple health bars and succumb after a set number of hits; exactly what and where you hit things is of great importance - hit a tanker in the fuel tanks hard enough and be rewarded with a satisfying secondary explosion, sometimes disintegrating the ship and everything small within a large radius.
Visually, it is quite dated now, something that they tried to fix in the sequel, which is somewhat buggy and sometimes broken. However, this original is very well polished, and I would highly recommend this gem of a game to anyone with half a brain and some patience.
If you do end up enjoying it as much as I have, the sequel may be worth trying, but be prepared for a general feeling of lack of completeness that is absent in this original. I wouldn't fault the devs too much for that, Paradox wanted them to release at an incomplete point and it was do-or-die for the studio. It has come a long way since release but the devs aimed a bit too high and fell short. This does not mean it is terrible, much fun is to be had, with a lot of new things to be tried - if you have the patience and an SSD to cope with the *occasional* CTD - (occasional is a relative term).
TL;DR: this is a very good and underrated game, buy it (it is also cheap), play it. Don't buy the second one if you are new to the series unless you are a masochist with too much money.