Naughty Bear

A surprisingly easy achievement to get. Select any speedrun challenge and complete it as fast as you can. Skip any of the bears which you don't need to get rid of and progress into the final area. Nothing which isn't obvious.

Once you've killed your main target however, head back to your hut, but do not use it's gate just yet. Instead, wait until the clock has one second left on it, then press the A button and use the gate. The clock will stop while your character moves through to the finish area, so that once the challenge is said to be complete, the timer should still say one second remaining.

Do the first Speedrun Challenge there is (it will be easiest) and simply do the "bear" minimum in order to proceed to the next area. In the final area, kill the target bear and then go to the exit BUT DO NOT GO THROUGH THE DOOR.

Wait until the timer reaches 0:01 and then go through the door to complete the challenge. Going through the door "freezes time", so upon reaching Naughty's cabin, you finish with one second left on the clock.