Sid Meier's Starships is one of the games that came along with the Humble Firaxis Bundle that I bought a few weeks ago. I've fired it up a few times since. I enjoyed a few games, but it doesn't really have the depth for me to play it for long.
Starships is a 4X game, but nowhere near the complexity of the Civilization games for which Sid Meier is most famous. There's not a whole lot of exploring, largely because you have only the one starship fleet to move around. As soon as you discover a new system, you'll probably want to expand into it, or exterminate the enemy that holds it (if you can). Building up the cities and other structures in your systems to exploit the resources they hold is important, but not particularly complex. The main focus is on upgrading your fleet, so that it can go into enemy strongholds and blow up the opposition.
The player spends most of their time with the starship fleet: upgrading and expanding it, repairing damaged ships, deciding where to send it each turn, and of course controlling it in battle. You can put the same components on each ship, or specialize: maybe one ship has strong shields and short-range cannons, while another has fewer defenses but heavy long-range lasers, and yet another carries a load of fighters or torpedoes. At the lower difficulty levels, it doesn't seem to matter much how you outfit the ships, since you're going to outclass the AI pretty easily. When I moved up a level or two, though, I found it makes a lot of sense to have specialized ships that support one another in a fleet strategy.
The tactical battles come in two flavors: missions for unaligned systems, and battles against enemy fleets. The former will ask you to accomplish some mission (escape from overwhelming forces, escort an unarmed civilian, wipe out specific enemies, etc) while the latter is a straightforward last-ship-standing brawl. In both cases there are various hazards scatted around the battlefield, mostly asteroids and space debris, which must be maneuvered around. Combat is turn-based, and each player has "battle cards" that can be played for various boosts to their side. There's plenty of room on the maps to outmaneuver your opponent (or vice versa) as well as special warp gate points that can provide some random surprises.
You also need to keep an eye on the systems in your empire, which produce the resources needed to support the fleet. Cities and structures in your systems determine how many resources you get. There's a technology tree with various ship upgrades that requires science from your systems, and wonders that can be built to provide special abilities. You start with one system, and expand to others via an influence system, where missions performed by your fleet add to your empire's influence on a system until it decides to join you.
The downside to Starships is repetitive play and the lack of depth. The battles can get tedious once you've put together a good fleet, since the AI's ships will run around the map to drag out the battle long after the result is clear. After a while, each battle feels the same. The technology tree and system building are interesting to learn, but there's not much variation in how to use them from one game to the next. Going up to a higher difficulty mitigates this to some extent, but I found that once I got to Hard (second-most difficult), my time-spent to progress-made ratio was disturbingly high.
I had a good time learning how Starships works, and playing a few games (on small/medium maps...I'd rather measure game time in hours, not days). It's a well-designed simple strategy game, good if you have an urge to do a little conquering. I doubt I'll play it regularly, but it's nice to have available when I don't feel like the full days-of-play experience of something like Civilization.