I really like this! It is a fun and cute little game. I have a few pieces of advice though:
1. The concept is really cool. I do wish you had made the NPC only start tracking how much he has said after the first time you talk to him though. I talked to him for the first time after I went through the door a few times, just as a test, and I think he just said one of his looping dialogue options (as opposed to the introductory dialogue).
2. This is actually (i think) a bug, not a suggestion, but when I ran out the timer, the game froze and seemingly crashed. (I don't know how godot handles crashes though so it may have just been frozen.
3. Add more enemies. Since it is a short game without a very complex level layout, I think the game would have benefitted from more interesting gameplay, which could be derived from having multiple enemies hindering you at once (even if you did not add more enemy types). I imagine this would be easy to do by just adding more spawn points and increasing the spawn frequency.
4. Parallax: Despite the level being quite short, it would still benefit from parallax to make it feel a little bit more alive. I understand you most likely did not have time to implement parallax, but if you do another game jam, I would recommend blocking off a few extra minutes to work on that (assuming you do another platformer).
Overall, this is great! I love the art style, it is super adorable! The idea is fun, and there is a lot of room to develop this further after the jam if you choose to (I personally like to do this to help me with programming quicker). If this is your first game jam, great job! Also, good job picking music and SFX, they both fit well in the game.