I own this game for a really long time, and I have owned it before it even was on steam, and boy is it good.
its not easy, its not like you're going to build a rocket and land on the moon int your first ten minutes. No it will take you hours on getting it right. Once you're on the moon, you need even more time to get to the next planet.
This is not a bad thing, it actually gives you a challange, and it forces you to really thing about what you're doing and what you want to get done, and how you're going to do it not the fastest way, but the most efficent way.
If you like space games, that give you challange, than buy the game. If like the more easy stuff don't buy it. Its looks simpel but its not.
9/10 really good game, that will challange you, everytime. ( and little green men, lets not forget about the little green men... that died... alot....)