okay so a like I'm Gona try help
The missing 1% is at QUESTS! Sooo
See the one thing where the flag inst colored? Were it's gray? That's an unfinished quest (side note IF you didn't find the quest it looks like this!)
If is gray and says "???" Instead of the quest name that means when you were playing you didn't do the thing to find the quest
Go to the world with the missing 1% (in your case world 1 ) click in all stages and try find the missing quest (remember it's the one that is grey!) once you find you could replay till you find
ooooor check a YouTube video with full gameplay with will probably show how get the quest you would have to search with the world and stage number like if it's world one stage five it will be EXEMPLE : "guardian tales world 1-5 3stars"
Well I tried my best to explain hope it helps π