No way someone's actually played the game. Anyways, the last two (I guess three) items are fairly well hidden, so I understand how one would have trouble finding them. Here's some help to nudge you in the right direction
- there is a secret path inside of egg quest (the platformer one). Following it may require you to go out of bounds at some point
- There is a building somewhere that requires you to return at a specific time. If you don't want to wait until then, it has a secret entrance
- The last item is locked behind the rest. Once you've collected all other 9, a barricade somewhere will disappear
I hope this was helpful enough without spoiling much