OK, so a quick bit of feedback that you need to know when making comics and is common to the vast majority of beginner comic artists: western audiences will tend to read things from left to right first, and then from top to bottom. So in the last panel of Wednesday's comic, I read "Do you hear sirens?" before the "Who the hell have I been spying on?" line, which doesn't seem to be the intended order. And in Thursday's comic, in the first panel, I read "Ja." before the "Are you Nietzsche?" question. And in the third panel, I read his exclamation before the "BLAM!" In the second panel of Friday's strip, it's not as bad, but her comment should really fit vertically between his two word balloons. Friday's bonus strip is just totally off all the way around.
You can fix this by crossing over word balloons, which isn't always as clear, but it generally works. You can switch the positions of the characters, but this can becomes somewhat confusing without changing the camera perspective. In 2D comics, that can be difficult. So try to position the characters in such a way that the dialog flows smoothly with the word balloons are over their heads and things still end up in the proper order, and think about how your dialog will fit into the panels. In the Nietzsche comic, for instance, why is Nietzsche on the left? He should be on the right.
This recent Diesel Sweeties strip is a quick-n-dirty example of how to do it right. The first bit of dialog is initiated by the character on the left, and his word balloon is in the upper left. The responding character is on the right, and his word balloon is below and to the right.
Eric (the Deacon remix)
The follies which a man regrets the most in his life are those which he didn't commit when he had the opportunity. - Helen Rowland, A Guide to Men, 1922