Notes for par scores on all levels:
Par scores are heavily influenced by par time.
Note: Competitive Score shows the time multiplier bonus; Regular Score does not. The time multiplier bonus still exists in Regular Score, it only shows up at the end of the mission. With Regular Score, you may not see the time bonus, especially on longer missions (credit: EaseAndInspire)
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:
Level: Tip of the Spear
Par Time: 15:00 minutes
Par Score: 30,000
Skulls: Catch, Famine, Fog, Thunderstorm, Tilt, and Cowbell (non-scoring but accelerates explosions)
At the beginning of the mission, you can go left to avoid some of the battle.
You only have to wait 90 seconds until the warthog drops, and afterwards you should really drive away to save some time.
The problem with this mission is that the gunner is usually terrible.
That leaves you with 3 options:
1. Try to deal with it
2. Get a co-op partner
3. Kill/leave the gunner and park the car to shoot yourself while slightly out of enemy range.
Either way, you're going to have to save time (and have some leftover multiplier) to get to 30,000.
The best way to save the time is after crashing the falcon.
Pick up a jetpack and stay right. You'll have to fight a few enemies, but after that you can jump on some rocks, and should notice some pipes. Those pipes will give you an enemy-free path the end of the mission.
For that last part, there will be an elite with a sword and two plasma cannon grunts. Best option is to grenade the elite and try to pick off the grunts slowly. You'll get a checkpoint arriving at this point so if you're at 35,000-40,000 points, you can get a few tries in before missing the 30,000 cut-off. Good luck!