>Can the game be considered a full release? No, for all intents and purposes, KSP should be considered still in early access state. The game is nowhere near being able to stand on its own legs both from a gameplay perspective (career mode is definitely not ready and balanced) and a stability perspective. There are still major bugs and memory leaks that shouldn't exist on a finished game.
>Are there big issues with the game? Bugs and instability are still real and frequent problems, as with every product still in beta. Ask in thread for details.
>What are the devs doing? Modified versions of popular mods are being included in the stock game while the game engine is being upgraded to its latest version. The most recent update (1.1) was supposedly going to bring a complete overhaul of the GUI, be 64bit friendly, have a refined physics/heating/aero model and generally perform better. While achieving some of these goals, the game is now more unstable than ever, with many users being unable to use the game at all. An external team with heavily questionable experience (Flying Tiger Entertainment) is being tasked with porting the game to PS4, XboxOne and Wii U, with a release deadline that seems to keep slipping.
>Should I buy the game? KSP is very enjoyable at first, then it usually needs to be modded to retain some sort of longevity, but doing so may dramatically increase the instability of the game. You will be very familiar with the word "Oops!". The Developers, Squad, have shown many times that they can't handle the project and are trying to squeeze all the money they can with the least amount of effort and with controversial PR tactics. The general consensus at /kspg/ is that you should torrent the game, not because the game itself is unplayable, but because most of us agree that Squad does not deserve your money.