To start off with, the password to Welcome_To_The_Game.rar is hashcat, simply enough.
We pop open that folder to get to the next level with, what looks to be, Brainf*ck.
I dropped that into a compiler, but it didn't work. Notably the brackets are reversed, which prompted "why don't I reverse every symbol?" (This can be solved easier with this reverse f*ck tool)
Here it is reversed:
++++++++++[>+>+++>+++++++>++++++++++<<<<-]>>>>++++++++++++.<------------------.>+++..++++.--------.+++.--------------.+++++.++++++++++.-----.+.+++++.------------.<---.>----..+.+++++++++.Next password is p4sswordisnoth1dden.
For the final password, we hash You_are_very_close.txt with MD5 to get the password aab2ee6281c7c190e7ae2c4cacddad52.
Finally we're at the flag! Trollcat{Ev3ry_f1le_h4s_un1que_h4sh_v4lue}