| In Kerbal Space Program, you access a seemingly limitless supply of little green men to explore the outer reaches of the solar system. Along the way will be success, triumph, and some of the most glorious failures in history.
Kerbal is a space exploration simulator where you design and build your own rockets to carry your inexplicably eager kerbalnauts to the Mun and beyond. The simulation does not bother with micromanagement details that would detract from the fun (air, food, boredom). Instead, you worry about thrust to weight for takeoff and landing, delta-v for planetary maneuvers, air density for air braking and reentry, and the like. The orbital mechanics model is accurate enough that often, if you do not know how to do something, you can look it up in a book or Wikipedia and expect the same thing to work in Kerbal.
Much of the mechanical physics part of the game is designed to allow things that would be plausible, but not possible in real life. The junction of each part has a given strength, and each part has mass and air drag. The model will show things like body bending and thrust/mass mismatch. However, parts have a given air drag even if shielded by other parts. As such, there is no purpose in adding nose cones except that it looks cool. There is actually a lot of things that have no purpose except that it is cool.
The sense of humor does a lot to add fun to what could otherwise be a dry simulation. Fuel tanks that were found on the side of the road, fuel pipes that are totally not a sewer pipe painted orange, engines that have less than 50% failure rate all make you wonder just what you are about to put your eager little kerbalnauts through. Then there are the kerbalnauts' observations like, "jumping on Minmus makes you feel like Superman", or, "You realize that surface of Minmus looks like mint ice cream. And you are hungry."
The controls of Kerbal map very nicely to a joystick. I highly suggest using one. It is much easier to launch a (highly) unstable rocket using a joystick than trying to use the keyboard. I happen to have chosen a joystick with a bunch of 4-way rocker switches. These proved to be excellent for using RCS thrusters for docking and landing. The keyboard is, of course, also usable.
The graphics for orbiting and deep space are often stunning. I have tried to post some good ones. The surface currently feels like a much older game. The land is low-polygon and the textures are very basic. The developers have stated that they are looking into dynamically generating surface data as the scale of the problem is too large to explicitly model the entire surface of every planet.
Finally, as of this writing, "career mode" is a brand new addition. Prior to this, the game ran in sandbox mode where all equipment is available from the beginning and there are no goals except those you set for yourself. Now you have to do "science" to unlock new parts. You start with such a limited selection that you cannot even reach orbit. You must achieve goals to earn science points to unlock new parts. These goals are purposely undefined. You find them yourself. I have gotten points for basic launch, flight through deep space, radioing back status, carrying payloads to different locations, and walking on new worlds. You can radio back results, but for more points, you have to get your spacemen back (alive).
Along the way there will be failures. Rockets will rip themselves apart during launch. You will forget to unfurl a solar panel and lose contact with your probe. You will begin the landing burn too late and hit the Mun at 200m/s. I currently have a lander lying sideways on Minmus. Guy may be there awhile. My proudest(?) disaster was scoring a direct hit on one of Jool's moons in excess of 7000 meters per second. I would have hit like a nuclear missile.
Kerbal is an excellent game for anyone who has ever looked at the stars and wanted to go there. It is also an excellent educational tool for the same. I have learned more about orbital mechanics and our own space history than I even knew I didn't know. A must play for people like me.