Gods Will Be Watching puzzle

I have recently created four puzzles. Once solved, the description of each giveaway contains part of the giveaway code for this final giveaway. In order to enter this giveaway, all you need to do is to solve those four puzzles and get the four remaining characters.

To make things easier, here are the links to the puzzles:

1
2
3
4

In terms of difficulty, I would say that two of them are simple, one is slightly difficult and the other is marginally difficult, although there is more than one way to solve it. You don't need to enter the giveaways, those are ultimately just place holders for this final puzzle.

The last character of the giveaway is: I

And you're already a fifth of the way there!