This is a very mysterious piece. I like the shadows on their faces. I get the feeling that I should delve deeper to understand their identities. The framing as well is quite unusual. Each character occupies a quadrant but they are all positioned differently. It's quite neat.
I have a few suggestions. Your watermark is positioned fine, but I feel like the title is just slapped on the top corner. It would look a lot better if it was somewhere else or just not there at all. All the characters' faces are well done. The woman's nose on the bottom-right side just seems a tad long.
Overall, this is a very nice piece. Keep up the great work.
Hey, thanks so much for this fantastic critique of yours, my dear, you just made my day! Both your comment and your star rating make me so happy, I'm all speechless, especially that you find this pic to be original and interesting. I kind of had the feeling that I messed this pic up, I wasn't even sure about uploading it, but that's really great to hear! Now I know it wasn't a mistake.
I'm also honoured and glad that you like my way of shading, since I put a lot of work into creating my own, unique style of drawing. And the framing and positioning of the characters is also something I'm quite fond of, I don't know why. Great that it looks good!
Sorry for the watermark, I've been given that topic a lot of thoughts lately, cause I think that mine might be too big and... I don't know. Ugly? Distracting? Anyway, I started signing my pics with my own name handwritten, that's a lot more traditional and less prominent, don't you agree? And yes, I fully agree, the nose isn't anatomically correct, I messed that one up. Unfortunately however, I couldn't change it anymore, since I've drawn everything with ballpoint. But thanks so much for the hints as well, I'll make sure I'll bear them in mind when working on my future paintings!