Starfarer has been in alpha
for awhile now, and anyone that pre-orders it gets to try it out. As one of those lucky people, let me say up front that I'm loving this game.
The performance is very good even on sub-par computers. The graphics are excellent, the particle effects are awesome, the weapons have serious punch, huge ships are still vulnerable to smaller frigates and tiny bombers, and the sounds/music are very good.
What you can do in the alpha
The alpha only allows you to play the "combat" section of the game (the full version will have a larger strategic layer similar to Mount & Blade) for now. You get access to a few scenario missions, though you're able to mod the game already to create more, or give yourself massive battlecarriers for fun.
The difficulty of these missions ramps up swiftly. You'll need to juggle control of your starship (with WASD, assigning weapons to autofire or fire manually via your mouse), with controlling your fleet (which includes such things as fighters, bombers, frigates, cruisers, battleships and carriers).
Why you should play it
It's unique. There aren't any modern games out there that marry 2D top-down arcade-like starship combat with real-time tactics, role-playing, crew modeling, and the "galaxy-view" (not the official name) of choosing when and where to fight, how to upgrade your ship, and outfitting/choosing a fleet.
Do you want a small team of incredibly powerful ships? Or a larger team of weaker, but easily replaced ships? The idea is that you can make it your own, while watching the impact of crew skill shape the battles. I can't wait for the full release.
