Glad to see that someone is also working on 3D projects, it would be cool if the maze was generated randomly, I also notice fps drops on my not very powerful PC, since the game is corridor-based, I would advise deleting and creating parts of the maze as the player progresses, this will not affect the overall picture, but will greatly increase fps, good luck.
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Thank you so much for the feedback! Despite the editor having hard times with a lot of 3d models, actually webgl render handles a lot of geometry, but not so much good on lighting/shadows. and there is a bit of freezing at the beginning of the scene where my code loads the cubemap textures, because its infiltrate the render pipeline it makes the game freeze a bit at that exact moment.
Also since the maze wasn't so much big I didn't went into culling technique. You are very experienced developer your feedback is very valuable for me. thank you so much!