It is a good all-round game. I consider it a RPG, because of the way the characters can get better at doing stuff and can get better gear and weapons, a tower defense because obviously your main concern is to defend yourself against outsiders and outside threats, strategy because you obviously need to really think strategic and know where to build stuff and how to plan your defense. Survival because obviously you need to survive, that is the main goal. You could also say this is a city building game, because everything you have you will have to build.
Also, I think it is a good game for environmental awareness, somewhat at least.
I like it because it is a game where you can almost be vegan. I created a vegan collective in the game where only when in desperate situations I would use meat and sell most of the leather and fur for profit. Most of which would come from animals already dead found around in the environment.