I liked the graphics, sound, and general vibe of the game.  Couple notes though, some of which the other comments touch on:

• For others stuck on the locked door, the code is "928".  I don't know why this is the code, since I count 10 candles and 3 book piles in this screenshot
• Every time you interact with the locked door and press the back button on this screen, the mirror shard by the entrance respawns.  You can use this to infinitely farm the shards.  I think similar things happen when you backtrack to previous rooms
• The door in this screenshot and the next level seem to infinitely loop into each other; I think someone else mentioned this door connecting to the exit of the next room instead of/in addition to the entrance, and that would explain this.
• As others have said, it would be nice if there was a restart/retry button in the game over menu.

Since I see you asking for how to implement checkpoints in the comments, I can try to give some short notes based on how I've approached implementation in one of my games before.  I do not guarantee that this is the best way, but it is a way:

I assume the doors are currently programmed to load a packed scene containing the next room.  If you create an autoload singleton that stores a variable identifying the current scene, and have the doors also update that variable, you can have global access to what scene the player is currently in.  I suspect you already have an autoload singleton set up since the number of mirror shards the player has picked up persists between rooms, so you should be able to identify the current scene with a variable there.  You can then use this information to have the retry button on the game over screen reload that scene.  You can also store other information you want to persist between room transitions in the autoload singleton, such as a set of boolean flags tracking which items have already been picked up, and reference those in the _ready() function of each room to determine whether or not to spawn the item. 

Cute graphics, and in general a cool idea. Some elements are a little unforgiving, e.g. I was stuck at the lock door so I could not move back for counting the items, also I got insta-killed by one of the beams. A retry button would have been nice as well.
Still a pretty good first entry - good job!

I couldn't guess the code. :( I tried 238, 248 and some more, but none worked.

It was funny to realize that the ghost gets surprised when shocked 'o'

Congrats on your game.

I loved this game! It's so cute and charming with only a few low points, like getting stuck while trying to unlock the numbers lock. I'm not sure how I messed up counting the objects in the room, but I guess I did? Either way, I had a lot of fun. c:

Great first release. I died shortly after the locked door. Managed to bruteforce the lock by only counting the stars and then trying 99 combinations :D

A restart button would have been nice, or some checkpoints. After the first locked door would be a good restart checkpoint imo.
I had 4 hearts but died instantly to the electric arc, so did not understand really what the hearts where for.
Other than that fun game :D

So first the notes I took while playing through:

• Firefox does not seem to like this game much. Not really the developers fault, but keep in mind players will try to resize the game window.
• Arrow keys, no WASD, no key rebinding.
• It seems dying sends to to a menu with only the option to quit. Not great?
• Exiting out of the keypad (update, also going back through doors) seems to respawn health and shards. Ended the game with 10 out of the supposed 5 as a result...
• There's no damage feedback and the health bar is tiny. I didn't actually realise I *had* health until I saw the first floating heart.
• Speaking of, the health bar is actually attached to the level, but only in the first level.
• The last level seems to spawn you at the exit rather than the entrance?

Besides those, its a pretty good first game! I'm sure with this learning experience in your bag, whatever you'll come up with next is going to be that much better :]

Fun game, I really liked all the faces! You did an amazing job! The one bug that I found was I could not go back to count all the candles, books and stars.