- Estimated achievement difficulty: 2/10 [Achievement Difficulty Rating]
- Offline: 22 
- Approximate amount of time to 1000: 4-6 Hours [Estimated Time to 100%]
- Minimum number of playthroughs needed: 1
- Missable achievements: Yes [see Road Map]
- Does difficulty affect achievements: No
- Unobtainable/glitched achievements: No
If you played Episode 1, you will have the ability to import that character's level and inventory into Episode 2. The game is built for this, so not doing so will actually be a handicap as the enemies will likely be quite tough.
I wrote up a quickhand "walkthrough" for the game to follow HERE. This is just a bullet point list of all the steps to take to ensure you don't pass by any of the game's events or missable achievements, and a brief map of the story events as well. I would highly suggest following along, as many things can only be done in very small windows of time. The game is extremely easy, and can be done on any difficulty you like though, so it's not hard by any means.
Pretty much every achievement that isn't directly story related can be missed, since once you reach the end of the game you are prompted to save. If you only use one save slot and save over top of your progress, you will need to start a new playthrough to unlock anything. You could also defeat every enemy in the game without doing 500+ damage and miss out on that, so save at least one battle arena to work on that.
Light Fairytale is a super cute RPG series. The chibi art style is great, and while not terribly inspired, the story and combat is solid. It does have a ton of missable achievements to watch out for, but with the story only being a short three hours or so, you could always plow through another playthrough if needed - but you should be covered by the guides I've written up, of course!