KSP is the only game i know that attempts to simulate space flight but at the same time as if that wasnt enough you get to actually build your spacecraft and the rockets or planes that deliver them to space.
This game will teach you a thing or two about astronomy , gravity and generally physics and orbital mechanics and it will help you understand why getting into space is so hard and why it is so important.

The vanilla game is enough to get you hooked for months , but the thing that makes this game even greater is its moddability. High quality visual mods for those people who want to get rid of the cartoony vibe of the game , hundreds of part mods for those who actually want to have their own gemini, apollo , soyuz missions to future technologies and scifi ships. Add to that mods that change the kerbal system to make it like our sol system both in shape and size ( now that will challenge you! getting to space wont be that easy anymore) or even new different star systems. And many other mods that will offer more science options, mfds for those who like to play from the cockpit....there is a mod for every little thing you can think of.

You can have a dozen of ksp installations each one with different mods like, have one with real solar system and real rockets and spacecraft that existed and exist today, keep a vanilla install , have another install to test mods ... there is no limit to this game.

Now once you get to space for the first time you will realise that you have a lot to learn and you should cause this game is a simulator. Im not talking about becoming an actual rocket scientist but at least to learn a few basic stuff like what is a delta v or an engines ISP. These things are pretty simple and you dont need a phd to understand them.
Then you should try out the mods! Learn how to mod the game and choose those mods you cant live without. And start a game and go forth and discover everything! put a satelite on every orbit ,build big space stations or huge interpanetary ships and go over a tour of the star system. Or engage on dogfights ,naval battles ,tank blitzkriegs... There are no limits to a sand box game and in this game you are not limited on a continent or a planet but you have an entire star system to explore and populate with your crafts. So being realistic this game has no end. Choose the sandbox option and learn from the russian nasa esa space programs and go have your own adventure. Take the time to deisgn your missions and crafts, be the space center director , the scientist and the astronaut all together at once.

a trully limitless game that one can play for a few hours or a few years! Now that the game will be released (1.1) with unity 5 i can see people playing a single playthrough for years. The only thing that can beat this game would be its own sequel.

As is with every sandbox game out there , this game can be whatever you want it to be. Ive seen people playing just to design crafts , other for combat , others to launch rockets , other go and make an entire space development adventure , other built cars and make races... there are no limits (other than gravity) to what you can do.

My biggest problem though was how big (how many parts) a craft can be. This is a huge issue and most of the mods and workarounds that exists cant really do much. Now in update 1.1 that issue will become milder...

KSP is the only game i know that attempts to simulate space flight but at the same time as if that wasnt enough you get to actually build your spacecraft and the rockets or planes that deliver them to space. This game will teach you a thing or two about astronomy , gravity and generally physics and orbital mechanics and it will help you understand why getting into space is so hard and why it is so important. The vanilla game is enough to get you hooked for months , but the thing that makes this game even greater is its moddability. High quality visual mods for those people who want to get rid of the cartoony vibe of the game , hundreds of part mods for those who actually want to have their own gemini, apollo , soyuz missions to future technologies and scifi ships. Add to that mods that change the kerbal system to make it like our sol system both in shape and size ( now that will challenge you! getting to space wont be that easy anymore) or even new different star systems. And many other mods that will offer more science options, mfds for those who like to play from the cockpit....there is a mod for every little thing you can think of. You can have a dozen of ksp installations each one with different mods like, have one with real solar system and real rockets and spacecraft that existed and exist today, keep a vanilla install , have another install to test mods ... there is no limit to this game. Now once you get to space for the first time you will realise that you have a lot to learn and you should cause this game is a simulator. Im not talking about becoming an actual rocket scientist but at least to learn a few basic stuff like what is a delta v or an engines ISP. These things are pretty simple and you dont need a phd to understand them. Then you should try out the mods! Learn how to mod the game and choose those mods you cant live without. And start a game and go forth and discover everything! put a satelite on every orbit ,build big space stations or huge interpanetary ships and go over a tour of the star system. Or engage on dogfights ,naval battles ,tank blitzkriegs... There are no limits to a sand box game and in this game you are not limited on a continent or a planet but you have an entire star system to explore and populate with your crafts. So being realistic this game has no end. Choose the sandbox option and learn from the russian nasa esa space programs and go have your own adventure. Take the time to deisgn your missions and crafts, be the space center director , the scientist and the astronaut all together at once. a trully limitless game that one can play for a few hours or a few years! Now that the game will be released (1.1) with unity 5 i can see people playing a single playthrough for years. The only thing that can beat this game would be its own sequel. As is with every sandbox game out there , this game can be whatever you want it to be. Ive seen people playing just to design crafts , other for combat , others to launch rockets , other go and make an entire space development adventure , other built cars and make races... there are no limits (other than gravity) to what you can do. My biggest problem though was how big (how many parts) a craft can be. This is a huge issue and most of the mods and workarounds that exists cant really do much. Now in update 1.1 that issue will become milder...