Hmm. Files shouldn't just disappear like that... Did you download the game from here or are you playing a browser version?
i downloaded it from here
do i need to download the changelog and encryption key?
You don't need to download the changelog or the key if the game itself is working fine. - This is the first time I hear about such a problem, I have no idea what would cause this, sorry!
I do apologize! I just checked it, and i thought i had bought the game from here but i guess i didnt lol but i just got it from here now