Holy molly that was brutal!
Well, I'm not against a game being hard or anything and that code system works well as a saving mechanism but I think there were some things that make the game extremely frustrating were it did not need to be, like the countless times I had to go back to a terminal accessible through some very difficult and punishing platforming just to not be able to copy the code cause the text passed too fast, and the only way to get the code to be displayed again would be reset time, input all of the previous codes and do all those difficult platforming again, dying a lot in the process, which felt very unfair cause I just managed to get the code, just wasn't fast enough to copy it. It would be as simple as letting the player close the dialog or displaying the dialog again every interaction.
Nevertheless I think the key aspects of a metroidvania were well applied here and the game fits well with the chosen theme, I personally enjoyed the difficulty (aside from the frustration I just mentioned), and think it was well done.
Congratulations for your submission and good luck!