Harmony’s Odyssey is an awesome-looking puzzle game. You have to complete the campaign on the hardest difficulty but that is very doable. It has no missable achievements and completion takes around 5h.
Approximate amount of time to 100%: 5h
Estimated achievement difficulty: 2/10
Minimum number of playthroughs needed: 1
Is there a good guide available: I wrote a guide with the diorama solutions, which you can find here
Multiplayer achievements: No
Missable achievements: No
Grinding Achievements: No
DLC-Only achievements: No
Speedrun achievements: No
Time-gated achievements: No
Does difficulty affect achievements: Yes, you have to play the campaign on the hardest difficulty
Unobtainable/glitched achievements: No
Harmony’s Odyssey is an awesome-looking puzzle game. 80% of the puzzles are dioramas in which you have to move blocks to the right position. You start with a few 2D puzzles but very soon they will be 3D puzzles, which look amazing. And a lot of the time after you finish a part of the puzzle things will start to move around, to make it even more magical. As an example, there is a level in the snow where the Ski will start working the moment you finish that part of the puzzle.
There are also some other different puzzle levels, finding the difference between 2 pictures for example. Or look for 15 seconds at a picture and then the curtains close, open and you have to point out what is different. There are also a few action puzzles where you have to move to certain objectives on the map without getting hit.
Harmony’s Odyssey didn’t have a resolution that fit my screen (3440 x 1440) but it was no problem to play it in window mode and enjoy the game.
Most of the achievements are very straightforward. You’ll have to play the campaign on the hardest difficulty for one of the achievements. I would recommend just doing this from the start so you only have to play those levels 1 time. If you didn’t do that, you can go back and you can also see on which difficulty you have completed them. Some levels are quite hard to finish on the hardest difficulty. For me, those were the levels where you have to find the difference and the action levels. On the hardest difficulty, you’re not allowed to click on the wrong item in those puzzles or have a short amount of time to complete a level. It still is very doable, but some levels might need some tries before you get them. You can get 2 hints in every level, so I used those in the levels with finding the difference in case I couldn’t find the last 2.
Another tip I would give is not to buy magic wands or music in the collection menu as you’ll already need most of the stars for the 2D puzzles to unlock the achievement for finishing all the puzzles. I got the achievement for the hardest difficulty just after finishing the campaign, which allowed me to play the other puzzles on an easier difficulty.
This review for Harmony’s Odyssey was written on 20 Oktober 2022, based on the current Steam version of the game which has 36 achievements at the time of writing this review. This information can be outdated, for example, when the developer adds or removes achievements or releases (new) DLC.