For this achievement you pretty much have to play through the entire game to get all of the Score X amount of points achievements. Thankfully the game is pretty short. I think it was about 5-6 levels. Didn't take me super long. To make this super easy go into your option menu and change some of the game settings.
So once you select English Version ORIGINAL MODE (or Japanese) ... your preference, go into options by selecting
then go to Game Settings. Make these selections:
Number of Players: 99
Continue: Yes (but doesn't matter, you have 99 lives)
Difficulty: LEVEL 1
Bonus: EVERY BONUS
Bonus Rate: 20000/40000
to return to the previous menu and select Return to game to restart the game with your new settings.
Now just play through the game. I pretty much just punched everything with
. You have 99 lives so you should easily get through to the end of the game even with a ton of deaths. I was dying all the time. I hit 100,000 points right before I fought the very last boss of the game. When I beat the last boss I got another 100,000 points, so if you're a little short for some reason by the time you reach him don't worry about it. You get 100K for beating him.
Enjoy another crappy ACA game