The video below is a full walkthrough of the game, including all "missable" achievements.
Nasty is unlocked by luring the gardener out of his garden, stealing his keys, and distracting him long enough to close the gate to his garden.
Timestamps:
0:33 - Nasty
8:10 - Yummy
9:50 - Devious
13:32 - Ghastly
14:25 - Unlucky
15:28 - Noisy
19:42 - Dreadful
20:42 - Pretty
26:47 - Careful
32:37 - Nimble
35:38 - Intrepid
37:53 - Elegant
40:18 - Cheeky
41:03 - Lovely
48:00 - Beautiful
Speedrun Guides Here:
https://www.youtube.com/playlist?list=PL-HeW6XkKdUJxso4NigWS...