There is a lot of things in the first playthrough:
1. The dev girl is still blocking the way to the employee's area (As of this comment)
2. When you are chocolate coated and use any item that gives fattening effect, all their sprites seem to show (See below)
3. Wallywix doesn't disapear after finishing the fight
4. Game softlocks when starting from the dev room and backtracking to the home village
5. Boss Annihilator doesn't one shot Wallywix
6. Gigi's immobile map sprite still doesn't exist (It's still only at the second fat stage map sprite)