First of all, a big thanks to @ProgramFOX and @causa-sui for this website, which is a nice resource to have for a game as tactical as crazyhouse. A few things:
I personally wouldn't mind a "Mate in ___" tag for each puzzle. In crazyhouse when there's one mate, there are often a dozen slightly less efficient ones. For training purposes it's not that useful to find m5 vs. one of several m6's, imo. I also think it would be great to have timed puzzles, since zh is played almost exclusively at faster time controls (could also combine this with the above and leave "Mate in ___" off of untimed puzzles).
Last thing - I have trouble with dragging piece drops, often it drags the entire piece jail and I have to click to cancel (using latest version of Firefox).
I personally wouldn't mind a "Mate in ___" tag for each puzzle. In crazyhouse when there's one mate, there are often a dozen slightly less efficient ones. For training purposes it's not that useful to find m5 vs. one of several m6's, imo. I also think it would be great to have timed puzzles, since zh is played almost exclusively at faster time controls (could also combine this with the above and leave "Mate in ___" off of untimed puzzles).
Last thing - I have trouble with dragging piece drops, often it drags the entire piece jail and I have to click to cancel (using latest version of Firefox).