All levels can be improved by a lot, but this is what I could come up with quickly to achieve platinum without Pikmin deaths. Running this RTA would make a fun misc category I'd say. No deaths so not a continuous run obviously.
CHAPTERS:
0:00 Start
0:18 1st Story: Bulblaxes
02:25 2nd Story: Snow Problem
5:48 3rd Story: Dig Deep
09:13 4th Story: Dandori Seas
12:47 5th Story: The White Key
17:44 6th Story: Gimmick Gambit
19:51 7th Story: One Fell Jump
20:59 8th Story: Crowded Kitchen
24:14 9th Story: Turf Turmoil
27:22 Final Story: The Purple Key