A great short-form game that captures your imagination.
What isn't up to you, however, is your final objective; either complete it or die. You're a courier for the Federation, which is somewhat of a cliched scifi take on space governments. You must deliver some message to the Federation fleet many sectors from your starting position. At that point, you must take down the Rebel Flagship to win the game and save the Federation. Yet FTL doesn't really focus on this endgame goal, instead letting you approach it somewhat at your whim. As you travel from node to node in a sector, you'll be steadily pursued by the rebel fleet, essentially forcing you to decide which nodes you want to visit before you must make the FTL jump to the next sector. You can visit the store, or answer the distress call; the store will certainly help you continue your voyage, but what about the distress call? It could be real; then again, it could be a rebel trap, and as a result, you've lost a crucial opportunity to replenish your ammo and fuel from the store. Yet again, FTL emphasizes choice.
One of the most intriguing parts of FTL isn't it's kind-of-there story or choice system, but its ship system. At the beginning of the game, you decide which ship you wish to take on your adventure. If you're a new player, you'll only have one at your disposal, though by adventuring and completing mini quests throughout the game, you'll find designs for other ships. Each ship type emphasizes a different characteristic of how you can approach battles. One ship is strong on ion-based weaponry, meaning you'll be able to disable your opponent's ship and strike a finishing blow. Another emphasizes stealth, allowing you to stealth past incoming missiles and strike back with your own. You can customize your ship's name and crew to your whim, which is a nice little touch. As you progress throughout the game, you can upgrade your various systems, from the oxygen system to the weapons system. Each upgrade allows for an increased ability of that system to function; for example, upgrading the shield system will allow you to eventually have a four-layer shield. FTL offers the perfect amount of interface with your ship; you're not designing the wallpaper for the crew lavatories, but merely controlling the overall systems. It's a very nicely implemented system that's both easy to use and immersive.
FTL is a game that you really have to experience on your own. It's quite cheap for the experience it offers you, and it occasionally goes on sale for next to nothing. While it may not have the depth of, say, Galactic Civilizations II, it is a really fun game to waste a few hours on. It's worth taking a look at, at the very least.