Overview:
-Estimated achievement difficulty: 6/10
-Offline: 20 (400)
-Online: 0
-Approximate amount of time to 400: 6-8 hours
-Minimum number of playthroughs needed: 3+ (Easy/Normal, Hard, Extreme, and additional plays of levels to earn money for the vault)
-Number of missable achievements: None. You can use Chapter Select after beating the game.
-Do cheat codes disable achievements ? No cheats.
-Does difficulty affect achievements? Yes, achievements for clearing the game on hard and extreme modes.
-Glitchy achievements: None
-Unobtainable achievements? No
-Extra equipment needed? No
Playthrough 1:
Play on normal or easy mode. During this playthrough you can grab most of the achievements relatively easily. Easy and normal difficulty have 5 heart containers to collect for an achievement where Hard and Insane only have 3 making Bless Me Bagpipes only attainable on this playthrough. If you miss any heart containers while playing don't worry, after completing the game you are taken back to Scrooge's office where you can buy art, dive into the money pit and select any levels that you have already passed. It's A Duck Blur is also only attainable on a easy/normal playthrough as magic coins do not appear in harder difficulties.
Playthrough 2:
On this playthrough you will be playing on hard mode. Beating the game on Hard mode will also unlock the Extreme difficulty option. Hard mode is the same as easy and normal where as enemies spawn in the same spots and the boss strategies are the same. The main differences in Hard mode is that you do not have unlimited lives, there is no map for you to view, you only have 2 heart containers to find and enemies take a full heart away when you get hit instead of half. You will be earning 1ups by collecting little Scrooge McDuck dolls along the way. It's good to search levels to find the heart containers since they will give you an extra hit each before you die and finding Mrs. Beakley since she gives you 2 health items and a 1up each time you run into her.
Playthrough 3:
Extreme! It's time to step it up and go for your hardcore extreme run. Extreme is just like Hard but health items are much more scarce and if you die you are shot back a bit and will need to replay some sections of the level. If you run out of lives you get shot back to the main menu. You should be familiar with the game now and have the basic boss strategies down.
Mop Up:
Now that you have all the difficulty and story achievements you will still to unlock all gallery items in the vault. If playing on Hard or Extreme you will earn more cash from a multiplier, also since those difficulties only have 2 hearts to collect the other 3 heart chests will hold treasures worth $1,000,000 which will help shorten the grind.
[We would like to thank lovemetal423 for this roadmap]