I figured out the code, you just have to write the prase DONT GET EATEN using the letters of the safe keys without repeating the numbers containing letters that you already used. But I'm not familiar with Discord to send my reward code and also the ending code. Could you explain what exactly may I do?
But I faced some bugs: 1) I don't know how to unequip the gun; 2) when I access one of the settings in the options menu, I can't go back to access the others. The game freezes in the first setting I accessed (in my case, the one that shows the game's controls) and I can only return to the game or see the same page everytime I access the Option menu, no matter clicking on Esc, RMB, LMB, Backspace or Left button (it's necessary to leave the game and execute the demo each time I wish to access the other settings (just to find out you can't change anything anyway); 3) when the zombie grabbed me, the command to push him ('Space'), didn't work and he killed me (I even desperately tried other buttons, but nothing worked) - frustrating my experience. But I gave another chance to the game and start all over again, so I understand that (or it's another bug) we have to push Space repeatedly untill the protagonist finally manages to free himself and push the zombie away. Since there's just 2 healing items, It's extremelly recommended do not let them grab you for a long time or more than 2-3 times.
Even though it's a short demo, the game should offer some checkpoints so that we don't have to start everything from zero if we die.
But it's a nice game. Hope you keep improving and finish it.