One of the best games I have ever played.

What is the goal of this game?

I'm not going to copy and paste the "About this game" section from the actual store page, so go there if you want to know how it works and what it really is about.
Now for what the "goal" is:

This depends on which one of the 3 gamemodes you are playing so I'm going to base this for each one of them:

Sandbox

In this gamemode you don't have to worry about anything other than having fun. You choose what you want to do and you have so many things you CAN do. To list some:

• You can build huge space stations around all of the planets/moons or maybe around the Sun (Kerbol).
  
• You can make nuke stations that are in orbit.
  
• You can catch asteroids and bring them to Earth (Kerbin)
  
• You can mine those asteroids and convert the ore into fuel for all your needs.

You get the point.

Science

In this mode, funding is not a problem. Your goal is to get every single research node and after that it turns into Sandbox.
It does not have contracts like Career.

Career

Here, as it says in the "About" section you have to plan your funding, the contracts and limit the money use as much as possible to become the best space agency on Kerbin!

Everything matters and mining is eventually going to be the money making machine. In my save I have ended up with as many as 14 asteroids in orbit around the home planet being mined and then burned up in the atmosphere when their ore is depleted.


It has thousands of mods on websites such as SpaceDock, Curse and the forum.

Also, I've noticed that some of the negative reviews are based of the fact that KSP does not have workshop support and downloading mods is painfully awful. To that I have to say NO!

An amazing person from the community going by the name "pjf" created the amazing CKAN (Comprehensive Kerbal Archive Network) MOD MANAGER back in 2014!!

This has a pretty simple interface, support for every single KSP version and support for hundreds of mods. (of course, it doesn't always have the mod you want but it does a hell of a job in helping with updating the ones that are really important to you)

I honestly can't understand the people that are leaving reviews (many with small amounts of hours) saying the mod support is bad when for 3 years there's been a ♥♥♥♥♥♥♥♥♥♥ mod manager.

The only problem with the mod manager is that it doesn't really integrate with steam (you can make it integrate but I didn't bother) so it won't track your hours spent playing the game. [That's
why I have a very small amount]


There are 2 building spaces :

The VAB

Short for Vehicle Assembly Building, this is the place where you build your rockets.

The SPH

Short for Spaceplane Hangar, it's the place where you build your airplanes and your spaceplanes.
The problem with them is that they have sort of werid controls but after you get used to them they are no problem at all. It is going to be annoying at the beginning if you are trying to make complicated vehicles but eventually it becomes muscle memory.


You probably noticed I've been pretty much only praising this game I do have this one issue with it.

Career contracts get pretty boring (even with mods)

The missions get really repetitive by the middle of your progress because you've been doing similar missions constantly. What I would recommend for the devs to add in order to fix this is the following : Make it so that contracts ask for things to be delivered to orbit around a certain planet or maybe for something to only be placed in a sub orbital trajectory and for extra cash you need to land your rocket. The twist is that you get the payload as a subassembly so you don't need to build it yourself and you won't have control over it after it's delivered. Maybe also some mining and delivering contracts to pre-built space stations that will unload after the mission is complete.


The game gives you absolute control over what you do and how you innovate your rockets/SSTO's.
The different modes give it a dynamic but science and sandbox are just about the same thing only with limitations.
Career is fun but should be worked on more.
Mod support is great even without workshop support due to the CKAN mod manager.
The game has you in the Kerbol System that contains 1 Star, 7 Planets and 9 Moons (if I counted correctly). Wiki Page [wiki.kerbalspaceprogram.com]