I can see lots of people complaining about textual errors, and I can see that you say you've fixed some, but there are still many more. The very first library book explains the Caesar cipher backwards from how you've implemented it, so even though you say you fixed a typo in there already you seem to have fixed it wrong. And your explanation of the rail cipher doesn't tell us how to account for an odd number of letters. I assume the top row would have more letters than the bottom row because we're supposed to start with the top row, but that gives us DOWSOUOTYRR which doesn't work.
Also the calculator is super jank. The division button seems to just divide by 100 which I assume is what the percentage button is supposed to do, and the percentage button doesn't seem to do anything. I'm sure there are other bugs in there but it's hard to say because I'm not quite sure I understand how it's supposed to work to begin with.
I appreciate that you tried to make a game like this, but you gotta pay way more attention to detail to make sure you get things right for this kind of game. When your players are relying so much on your instructions, the intricacies of the instructions need to be correct.
EDIT: Okay, now that I know the solution I can see what the problem was. You explained it backwards again. This is probably because you're confusing encryption with decryption. This is understandable because you need to explain to the player how to decrypt when you're the one doing the encrypting and not the decrypting.
I don't actually know which way is which, but I'll assume the way you explained it on the last page of the library book is how to encrypt a rail cipher so I'll call it rail cipher encryption, and the way you've implemented it in the game (and apparently how you explained it before the last page) is how to decrypt a rail cipher so I'll call it rail cipher decryption.
Rail cipher encryption is splitting the word into halves and interlacing the two halves together, much like shuffling a deck of cards. That's why I needed to know what to do with an odd number of letters, because I didn't know which half the middle letter should go in. Rail cipher decryption, therefore, is recreating the two halves by sorting odd letters into one half and even letters into the other.
If we were to decrypt LTRTRIEAUE this way, we would get LRREUTTIAE and not LITERATURE. If we want to encrypt LITERATURE with a rail cipher, the actual code should be LAITTUERRE. So like I said, if we try to decrypt DWOOYROSUTR using rail cipher encryption like you explained instead of rail cipher decryption like you wanted us to, we get DOWSOUOTYRR instead of DOYOURWORST. And if we were to "encrypt" DOYOURWORST the way LITERATURE is encrypted in the book (using rail cipher decryption instead of encryption), we'd get DYUWRTOOROS.
On further examination, I think the calculator percentage button does work as a division button so you just swapped the labels.
I don't know if you'll read these edits, but now that I've beaten the game I'll provide a list of other mistakes I found.
1. Typo in the readme: "Do with is as you please."
2. It's unclear if we're supposed to click on the words "Princess Diana" or her picture.
3. Book 4 explains the cipher backwards again but this time I was prepared.
4. I never unlocked book 5. I'm guessing I was supposed to input a three-letter code in the I SEE YOU app to unlock it and I wasn't smart enough to figure out the code, but if that's not the case then it's pretty weird that it lets you highlight the letters like that.
5. With M + D * Y, you've put multiplication after addition and expected us to know that we're supposed to disregard the order of operations and just calculate it from left to right. Also, you called it a SUM even though the last operation is multiplication which makes it a product.
6. In book 6, you've written "it's both a combination of." I'm guessing English isn't your first language but this redundancy makes it incorrect. It should either say "it's both" or "it's a combination of."
7. In book 6 you say to use the row and column even though the column is supposed to come first and you don't mention that. We can only see which one comes first by interpreting the examples.
8. In book 7, the message ending in VDVX does indeed translate to LITERATURE, but it differs from the message you've shown in the earlier grid which ends in XDVX. It seems a bit strange to have just one letter be different because it looks like it should be the same message in the grid examples and the last-page explanation.
It turns out no one has been able to crack the Crypt Killer's codes because he explains them so badly! That was his criminal mastermind secret all along!
Anyway, thanks for the game, glad to see it, happy to play it, hope to see more :)
Hurr durr, I just figured out how to unlock book 5 when I watched FutureCopLGF's video and remembered what the I SEE YOU app was originally. I didn't need it of course because the pigpen cipher is pretty intuitive. The letter buttons in the pigpen key flicker a bit but I assume that's intentional for the palm pilot effect.
Another bug for you: books 1, 5, 6, and 7 can all be clicked while another book is open. Books 5, 6, and 7 will then open automatically after you close the current book, but that doesn't happen for book 1.
I updated my rating because I can see you're so committed to improvement.
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