Annoying Achievement here. To get points, you basically have to apply every technique available. Meaning, using Advancing Guard, Crossover Assist, Crossover Counter, Aerial Crossover, Aerial Counter. All these things will contribute to your "Advanced Defense and Advanced Attack" stats when you earn points. Try to advancing guard constantly, and when you have the bars required, use Crossover Counter (When your guard shield comes up, press towards the opponent and hit the assist button, takes 1 special bar). Only attack by using assists (LB, RB) as it contributes greatly to your attacking points. If you're slick enough, you can always guard or Crossover Counter or Advancing Guard while never taking damage, this will give you MASSIVE points in the end.
You are graded in this fashion;
Stability (How much health you have in the end)
Basic Offense (How many basic combos, specials, and attacks you performed)
Basic Defense (How many attacks you blocked)
Advanced Offense (How many Advanced combos, Aerial Crossovers, Crossover Assists, Crossover Combinations you performed)
Advanced Defense (How many Advancing Guards, Crossover Counters, Aerial Crossover Counters you performed)
Arcade Mode (The sum of all the above)
The max in each category is 50,000, so if you played absolutely flawlessly, you would end up with 250,000 at the end of the match. Meaning 1,750,000 is literally the highest amount of points achievable in arcade mode.(This is nigh on impossible)
A perfect win usually results in 60,000 points a match. With 6 Matches+Galactus, this will NOT be enough to get this achievement. So don't just try to perfect the opponent.
You need to shoot for 80,000 points a match (You'd have 480,000 by the time you fight Galactus, and you will always get more then 20,000 points from that fight) This can be VERY tough and VERY tedious.
Okay to go into some detail about earning points;
Earning a perfect will give you 50,000 in the Stability Category, however getting hit just once will immediately drop you to 20,000, and keep lowering the more you get hit.
A Crossover Combination is worth 2,000 points in the Advanced Offense category (Note:It does not matter if it was a 2 person or 3 person combination, still worth 2,000 points)
Using X Factor is worth 2,000 points in the Advanced Offense category.
(As this is once per match, that means 14,000 points per Arcade Run)
Successfully landing a Snap Back is worth 1,000 points (Maximum of 2 times per match, so 4,000 a match and 28,000 per arcade run)
A Crossover assist is worth 250 points in the Advanced Offense Category (This can be earned a maximum of 24 times per match, so 6,000 per match and 42,000 per arcade run)
A Crossover Counter is worth 2,500 points in the Advanced Defense Category (Making this the most point efficient use of your hyper gauge bars, however it can only be done 2 times per match, so 5,000 points a match, 35,000 points per arcade run)
An Advancing Guard is worth 650 points in the Advanced Defense Category
Switching out your character is worth 1,500 points (This can only be earned 6 times per match, meaning you can earn 9,000 points per match, and 63,000 points per arcade run just from switching out!)
Obviously Very Easy mode is the right choice when aiming for this achievement.
Make sure you choose infinite time to insure you have enough time to farm your points.
This guide assumes you know how to perform the advanced mechanics of the game, if you do not check out the other guides or send me a message on Xbox Live and I will be glad to try and assist you.
All information in this guide was gathered from me studying how the points are awarded, no outside sources used.
This is a tough one, takes some time but it's worth it. As of 11/16/2011 only 5 people have over 500,000 points, so getting this puts you on the front page of the leaderboard! Good Luck.