Really cool game, I genuinely learned a lot about ciphers while playing this. Before this game I only really understood how Caesar Ciphers work :)
Reading the comments below, I see you guys did this in half a month rather than a whole month. That is super impressive as this game is pretty well fleshed out! As mentioned before, the only real major thing that I would add is some automation after you figure out the code of the ciphers, as it can get a little repetitive after a couple of decoding sessions.
All in all, great entry team!!