About the second key, I can only say that the lantern will shine the answer for you.
Thanks for the feedback everyone. ^^
Hey guys. o/
Yes, you can win the game. There are 5 itens to collect.
Maybe I left the difficult a little too high. Unfortunately I only had time to test it with 3 guys and they beat the game after 3/8/9 times. The major challenge being finding the second key.