It's still an alright single player experience, but you'll definitely be missing out if you don't have at least one other person to play with. Like with any multiplayer game you won't have as much of a reason to come back to it if you don't have someone else to play with.
My recommendation:
Pick it up if you're a Nintendo fan (The Sub-Space Emissary and all around Nostalgia should be enough to warrant this choice).
Pass it up if you're not.
Edit: Oh, and the demos range from the shortest being about 40 seconds (for the original Donkey Kong) to 5 minutes (for the Legend of Zelda: Ocarina of Time).
CIHYFS?







