Firstly congratulations on a using a unique approach to the challenge!
Composition:
A little bit too busy , but still ok! I am glad you used black and white! I think colour would have been too distracting.
Exposure: good focus and lighting,
Suggestions
Take a crop from the middle to cut down the amount of raindrops and focus on those lovely clear mirrored images.
I can't find Waldo in any of the raindrops, even with a magnifying glass. Good job of hiding him, but we are supposed to be able to find him eventually. Don't tell me he the shadow through the glass, because in my opinion that doesn't meed the challenge. But that's just my opinion. But it is a neat photo of the raindrops.
I get it. Challenge met. Odd shapes, but I like it. Not alot of detail, except on the glass itself (kinda distracting, but I shouldn't suggest you wash the glass). Interesting, but I would like to see more detail. 7 Swash