Thats total BS. I finished the game once in 4 days and as one of the trophies is to see all the endings they would have to finish it 17 times. Even a fast play through took me 2 days. Just the load times is a few hours then there is the gameplay. It takes at least about 4-5 mins to load each level.
When it was first talked about before it came out and to hype it up they said it had 26 endings but it looks like it ended with 17... I've seen 3 so far, on my 4th play through now.
The DLC has 5 endings and I've only seen 4 of them. I can't work out how to do the last one yet but I'm still trying.