You need to play the tutorial and a bit of single train mode before being able to play this mode. For this achievement you need 2,000,000 points. It is somewhat simple to obtainwithin the 5:00 time limit. I'd say 3/10 on difficulty. If you have played the original, you should know the basics. What is a little different is ghosts don't kill you right away when you touch them. You have to make them mad before they can kill you. Levels end when you eat the fruit that appears. The early levels do not require you to eat every dot, but if you do you will get a bonus bomb. When used, these warp you back to your starting point of the level. Also, in this mode you can have multiple ghost trains. When these are eaten they give you a ton of points. These can only be eaten if you eat a power pellet though these will not appear in every map. When you do eat one of the power pellets a gray line will appear and the ghost trains will ALWAYS be somewhere on that line. If you eat the main ghost you automatically eat the rest of them. Last, try your best to save bombs. These, along with lives, give you bonus points when time is up. A bonus life in the shape of a tiny pac-man appear every so often so try your best to grab it.
Edit in reply to NBA Kirkland when asking the best strategy:
What i do is get every dot for the first 3 screens for the extra bombs and bonus points they give at the end. After I get my first power pellet is when i just wake up as many of the green ghosts as i can while waiting for the fruit to appear on those maps. When a map with a bunch of green ghosts appear i wake them all up, eat the power pellet and gobble up the ghosts. I've never gotten less than 2.5 million doing that.