Great video!
Just a question:
If I have 3 keys. A blue, a red and a green key. Blue key is for blue door, red for red door and green for green door. Then I can use a Hash Table as you explained in the tutorial. And it works great, but what do I do if I have many blue keys? I tried that, but it didn't work so well, because when I pick up the first blue key it will be added to the Hash Table, but when I pick up the next blue key, it replace the previous blue key. I know why. It's because I use the same Hash Table key. Is it a way to do this without name the Hash Table keys, Blue Key 1, Blue Key 2, Blue Key 3 etc.
It's not a problem to do this without Array / Hash table.