I have started playing the meta game and it is very doable. There are some ins and outs however. The task of scoring 15ooo points is a lot, but with the right combo of skulls and difficulty level, this can be done. I have just completed the first two levels and easily I might add. Here is how I did it. You should get ALL the skulls by the way before attempting. Here is a very helpful page with videos.

[Here is a list of the skulls, their locations and what they do]

The BEST method in my opinion is this:

Play the game on normal. Yes, I know you do not get the multiplier for difficulty, but let me finish.

Use these five gold skulls: Tough Luck 1.5x, Catch 1.5x, Fog 1.5x, Famine 2x, Thunderstorm 1.5x.

This will give you a 10.5x multiplier. A hell of a lot more for playing this on Heroic because you are penalized for dying; heavily I might add.

These silver skulls: Grunt Birthday party(explosion from headshots), IWHBYD(why not, funny as hell), and Catch(free grenades)

Take your time. You will not need the Time multiplier because if you use headshots, grenade sticks, some melees and not dying, you will easily clear the limit. Also kill vehicles when you can. Points are points.

Here is my Bungie.net profile in case you think I am full of shit.