Pretty sweet setup you have here. The only thing I'd say is off is the way you've written the lettering. It's angled, but relatively clean and neatly printed, so it I don't think it really embodies the Jokers instability and state of mind. Perhaps if the writing was a little more messy, with some paint drips trailing from the letters, so it looks fresh. Try changing the sized of each Ha to show imbalance or instability.
If,however your concept has a meaning behind the neat lettering, it may well be fine. Great job.
If,however your concept has a meaning behind the neat lettering, it may well be fine. Great job.