There are those indie games that truly captivate your attention and keep you engaged for hours on end, and you know it's a gem when you find yourself spending the whole evening mining, collecting, running and blasting your way through zombie space.
MiniMax Game's Space Pirates and Zombies was developed by two blokes in Canada and boy, for two guys this game sure does outstand in the indie pool. You start out as a little 4-hardpoint ship, just plunderin' the good plunder. As you progress through the story you'll find out something crazy has stirred up at the centre of the universe. Something that allows flesh eating monstrosities to biologically enhance and drive their own ships, despite being mindless husks. The story has an enormous gravity to it; as the plot progresses, your fleet of AI-controlled ships, blueprints, hull types, weapon types, subsystem effectiveness, mining ability and the like go on the up as well. Doing this makes the player feel the gravity of the situation: there's a huge threat of space zombies capable of surviving without oxyen floating about at the center of the universe and you're going to need all the help you can get.

I suppose the reason why I find this game so enjoyable is an amalgamation of perfect game dynamics; the tactical RTS-like command of your own ship, with a main player-controlled ship and up to 4 other AI controlled ships, all of which are available for the player to directly take control of any time during flight. Missions are undertaken for either the civillians of a star system or the UTA - the universe's private military force, and doing favours for one faction often angers the other. The ever expansive tech tree is a delight, as well - research data, the space equivalent of experience points become increasingly important to get that rank of weaponary, subsystem, engines, or armour that you know you're going to need at the current system. As time seems to go forward when you jump from planet to planet and star to star, the players get used to planning a route according to a star systems ecosysem, 'difficulty' (measured in civillian or UTA strength) and managability.

With the addition of vicious money-hungry bounty hunters to the mix, I've never enjoyed any space-sim-top-down-physics-based-shooter as I have with this. I've found myself dedicating chunks of my gaming sessions to mining, exploring, trading, or fighting in this game. And when you finally get all the blueprints, all the ship hulls, and high-tier tech skill upgrades, you're still finding yourself having a blast dealing with pesky space zombies. In a nutshell, I haven't quite experianced any game like this but I can sum it up into two expressions: YARR and BRAINS.