Before play KSP I have no ideas how hard it is, to design something that is able to go to the space and come back in one piece.
Exploration is human's nature, our curiosity drive us into the deep space imagining what will be waiting for us. Well, lucky you, if you are a science nerd, rocket fetish, got a lot of A plus on you Physic's examination, KSP is the perfect game for you to spend some time for a adventure. From experience, KSP has no flaw, apparently my expertise aspects are limited to artistic titles, video game, design. For science, I'm not even amateur but if you ask me if there are any features that I wish was in the game or will be added, I would like see more solar systems and most importantly flora and fauna.
So far my suggestions seems intriguing, but there's a problem for gamer who wish to see faster results, if so,I warn you that you won't go further into the game. That will be a waste of money, in my opinion. KSP has some necessary built in tutorials but that won't be enough for someone like me, amateurs, to get into orbit. Don't worry, that doesn't mean we are just going to watch others building fancy things. There is a joke about KSP, whoever ask a question in KSP community thousands reply "Scott Manley"! Luckily we have our self a mentor on Youtube to teach us all the essentials that is required to "enjoy" the game.
Assuming you are an amateur like me, whichever mode you started you will either get overwhelmed by all the parts that is displaying in front of you and you can't even make a damn thing out of them, or you are staring at a 4 or 5 parts and you have no ideas where this is going. If you are not a patience gamer, KSP can only be a cheap fun, you build some weird aircraft and spacecraft, fly around, click some buttons. Then KSP is definitely not a game for you and that's why spend times watching Scott Manley's tutorial is required.
I had a hard time to learn the essentials, but Scott Manley is professional enough if you pay attention to his lessons. Most of the gamers will probably think, why the heck do you need to learn to play a game? Well KSP provide a strong realistic feelings (career mode), gravity, weight, budgets, design possibly everything that is related to build a spacecraft in real life is in this game. You can play it casually but you won't fully dig into this game.
Failure will be inevitable, especially to people like me, I know very little things about spacecrafts, going through atmospheres, get overheated, can't even lift off the ground, can't return to ground, can't make a round orbit, suck at rescue mission, can't go to "moon". These frustrations are necessary but will eventually beat you, and you will rage quit. I remember I was doing a rescue mission where there are 3 astronauts need to be saved in low orbits, I successfully extract all of them but I got overheated exploded when return to "Earth". Yes, I didn't save it.
Overall, KSP is a high quality space simulator, and a lot of potentials for you to discover, forgot to mention that KSP fully supporting mod which make this game even better! I do suggest you play the original game first then try some new mods. KSP gave me a lot of good memories, the moment that I reach the "moon", the moment that I reached north pole, you really feel that all that efforts worth it and it is so thriller and satisfying to achieve something in KSP. That's what makes this game so special, after I became a decent player, I started to realize why conquering space is not that easy, as the title says. A true experience about learning and practicing space and aero technologies that you will ever go through. Highly recommended! TO SPACE!