Notes for par scores on all levels:
Par scores are heavily influenced by par time.
During "par time" all scoring is tripled.
After "par time", you have 10 minutes where your multiplier goes from 3.00x down to 1.00x. For example, if you kill an elite for a pop up of "+200", the score will show 600 during par time, but then will trickle back down to 200 when the multiplier goes down to 1.00x (and will be 400 if the multiplier is at 2.00x).
After the "ten minute down to 1.00x" period, one of two things happen:
1. You get a 2nd grace period, of about 10 more minutes. Multiplier is already at 1.00x so nothing else happens with it.
2. All positive scoring is done. All kills show up as red "0", but you will still lose points for dying, team kills, or checkpoint resets.
After that (Par time + 10-minutes + possible grace period), all positive scoring is done no matter what. Negative scoring is still active.
If you've already achieved the par score, you'll still have to beat the level while making sure you don't have enough negative scoring (deaths) to go below it.
For this specific mission:
Par Time: 20:00 minutes
Par Score: 30,000
Skulls: Catch, Famine, Fog, Thunderstorm, Tilt, and Cowbell (non-scoring but accelerates explosions)
At the beginning of the mission, keep sprinting until you run into the suicidal grunts. You can't exactly run by them, but you can shoot them down quickly. Brutes in this level are much different than elites:
1. You can easily stick them with grenades
2. They can go down with 2 melee hits usually
Use that to your advantage to work through the level.
After you pick up the jetpack, use it to try to skip some parts of the level if possible as this is a long mission.
If you're over the score by the time you get out of the falcon with your multiplier ticking down, you can save time in the final section. Grab the mongoose to drive down to the first signal to activate it. You'll jetpack up to it and then jump back down to the mongoose. You should get a checkpoint but the game would give them sometimes and sometimes not.
Drive to the 2nd one (in between 2 tanks) and do the same.
The 3rd button to press is in the building back where you started the section, so drive back to it, and fly up a floor. The button is facing the front, so you should be able to jetpack over to it once the jetpack refuels. DON'T walk to it as the brutes will find you. Good luck!