Kaze and the Wild Masks

*MISSABLE*

This is the only truly missable achievement, since once your save file reaches two hours, you can no longer obtain this achievement on that file. It's a shame considering they could've just let your time trial runs add up to a total that you could work to improve, but unfortunately that's not the case here. You need to beat the game on a save file where your total time is under 2 hours.

Fear not - this isn't nearly as bad as other speedruns out there. A perfect run of the game with no deaths would most likely clock in just under an hour, giving you plenty of time to spare. Personally, I had a solid 8-10 deaths (including one over halfway through the long final boss fight) and I still finished with a time of 1 hour 17 minutes. So, you don't need to be anywhere near perfect. It should go without saying, but you should obviously:
 

• Skip all cutscenes by pressing 
• Ignore all collectibles entirely (crystals, bonus crystals, letters)
• Play on Casual so you can take more damage and have more checkpoints
• Ignore bonus levels and any medals of any sort

Basically, treat every level like a time trial and just go full speed, since things line up perfectly when doing so anyway. You'll be surprised at how fast it goes when you don't need to pay attention to any collectibles, it doesn't matter if you take damage, etc. Just beat the level and immediately move on to the next. Beat the boss and jump right to the next world.

Personally, I did try this, but I assume if you die continually in a level and aren't happy with it, you could dashboard out of the game. The game only saves progress after beating a level. For example, when I died over halfway through the final boss fight, I could've dashboarded to save that lost time. Only reason I didn't is because I knew I was way ahead of par time. So keep that in mind. The only troubling levels will likely be the Dragon Mask levels and the final boss fight. But again, you have so much room for error here that it shouldn't be an issue. You can benchmark yourself at something easily attainable such as 20 minutes per world. It'll have you finishing in 1 hour 20 minutes, which I would say is a pretty reasonable time with a handful of deaths per world. You don't want to benchmark at 30 minutes per world because that'd cut it too close. If you play this run as soon as possible after your 100% run, you'll likely find this pretty simple. The first two worlds in particular will feel very easy after the last two harder ones. Boss fights will also feel pretty easier aside from the final one. Utilitize videos as needed, such as those in Wait... What? (100G), but really, as long as you do this after your 100% run (and don't wait weeks, months, or years), you shouldn't have any real problems cruising through most levels. Dashboard any you really screw up on, and you should have no problem finishing in under 2 hours.

This achievement will unlock as soon as you land the killing blow on the final boss, if successful, in true speedrunning fashion.