I absolutely love your enthusiasm, i can tell your really passionate about this project and im sure the more you continue to work on it the more you will gain, whether it be success or improvement of your drawing skills.
On the critique side of things, i would have to mention how much i noticed the smudge tool, even the barcode box has a feathered edge to it! I would advise that you sharpen up your lines, maybe try to get away from smudge tools, or if your comfortable with this way of working then maybe just tighten up your character sillhouettes? i guarantee that the narrative in your comics will become ten times more easy to read for the viewer.
Proportion is important, but for you cartoon style, i wouldnt say its the be all and end of all. I dont know which genre your comic falls into, judging by the tone set out by your colours and title i would have to say that its a comedy? I dont know if im right, if not then you might have to put more consideration into value and colour to adjust the tone of voice.
If it is a comedy, i doubt readers are going to want a heavy backstory. In my opinion, if i was reading it for comedic value... i wouldnt really care about vampire mythology, if it was truly entertaining im sure most viewers wouldnt even wonder why he was walking around in daylight.
I hope this helps, if this hasnt then its a weakness on my part as critiques are something im still learning!
All the best.