Overview:
-Estimated achievement difficulty: 3/10
-Offline: 10 (170)
-Online: 2 (30)
-Approximate amount of time to 200: 8-10 hours
-Minimum number of playthroughs needed: 1
-Number of missable achievements: None!
-Glitched achievements: None!
-Do cheat codes disable achievements?: No cheats
Introduction
Castle Crashers was really meant to be played with 3 other people. If you are unable to, for one reason or another, you can get by with using multiple controllers at certain parts. At the four boss fights that free a princess, you will need 2 controllers to be able to fight for a kiss from the princess. You will also need 2 controllers to pass the first area without attacking. At any other point in the game, you will need 4 controllers to knock out and revive the other 3 knights. Aside from that, you should be able to work your way though and complete the remaining achievements with relative ease.
Step 1: Story Mode
The story mode is rather linear with only a few spots where you will have to backtrack. Fight your way though the waves of enemies and feel free to spend your experience to tailor to your playing style. Don't forget to factor in bonuses from animal pets or weapons as well. If you want the Conscientious Objector achievement from the start, make sure to start with a second controller and use it to do all the attacking. Keep a list of the animals handy and unlock them as you go on. Also take note of which boss battles will free a princess. If you're playing alone, get your second controller out. If you're playing with others, decide who gets the kiss and go back through if other people need it. All levels can be played again, so don't fret if you miss Deer Trainer or Maximum Firepower. Be sure to keep your inventory stocked with potions and sandwiches as they are always helpful.
Step 1.5: Mop Up
You can replay any level at anytime to hunt for weapons, animals, or just get some experience. After completing the story (or anytime you want really), you can head back and find any animals you missed or didn't backtrack for.
Step 2: Online Play
For the final two achievements you will have to complete some ranked matches. 40 Arena matches and 20 All You Can Quaff matches. All You Can Quaff is a button mashing game in a race to eat various foods. There will always be 3 other opponents, one of those has to be another person. The Arena contains various versus modes with the most popular type being straight up melee. You play with your characters from the story mode, so always try to pick your strongest character first, as there can be no duplicate characters in a game. If you have a boosting partner, I found that choosing the Beefy type match can be completed the fastest.
Conclusion
Nothing stands out in Castle Crashers as very difficult. Take your time and enjoy the experience though story and be prepared to dedicate some time for the online matches.
[x360a would like to thank jukkakhan for this Road Map]