A bit of misinformation in the last few posts. It's no wonder, since Frontier Developments communication is the worst of their mistakes and my biggest criticism of the game.
Yes, it's an MMO, but at the same time pure singleplayer if you chose so. It it always online though, which is required because of their complex background simulation. This is a letdown, but unless you just can't get an internet connection, it probably won't limit your enjoyment of the game. Frontier should have said much earlier that they might have to cut the offline mode.
There are missing features, but not numerous. The ingame communication should be much better and there should be missions to allow coop play. This was promised, but they didn't say they'd have it implemented by the time of the release. They are working on it.
The biggest missing features are of course leaving your spaceship, running around in it/on stations and planetary landing. But those, they said since the kickstarter two years ago, will be implemented in the next two expansions, in around one or two years.
The game doesn't hold your hand. There are some video guides on youtube though, it you need help. In time this will probably be the best space sim ever, if Frontier can get enough funds. Right now it's at 20% of what it's going to be I'd estimate. Keep that in mind if you want to give it a try. Or just wait for a year or two.
