Welcome to the video to show that the Grand Slam achievement in PDC Darts just does not work.
I'm about to throw the final dart here in the World Championship, which is the last tournament in Career Mode.
Just to show you what I've done here so far, I've played the first TWO seasons of PDC Darts, that's 13 tournaments, without turning the xbox off, or quitting out of Career Mode.
OK, I refute that - the Grand Slam achievement DOES work, and as you can see it has just unlocked.
So what I did:
Played through seasons 1 and 2, rarely ever pressing start,
Only letting it save when it auto saves
Barely losing 30 or so legs across the career
As you can see, 10k darts thrown and all the trophies.
As a time scale, today is Christmas Day, so 25th December. I started the first season on the 20th December, and have had a mixture of sleeping and playing this game for the past five days. And some drinking.
So there you go, the Grand Slam achievement does unlock, and PDC Darts is fully completable.