No, this is definitely not a fantastic game, but it isn't as bad as people say it is. The story is very simple. Aliens invade the planet (cliche). Duke saves the planet. But the story isn't what Gearbox was aiming for. They were aiming for a funny and quirky game. I had fun through the campaign, this is simply because the game is fun, stupid and messed up.
Yeah you can go pick up poo from the toilet and throw it around. Yeah you can pee in the urinal for hours and hours to your heart's content. Yeah you can go to a strip club and watch some pixelated strippers shake their booties. But that's what Gearbox intended and I think they did a damn good job making this an entertaining game. That said, is this an amazing game? No. Is it a fun game? Yes. Should you pick it up? It all depends on your cup of tea.
If you want a game you can just chill and play through with a few laughs along the way, then yes, this is the game for you.