Cool! I like the effort to use different mediums and graphic styling in the piece. Also like that the guy is more straight lined, wheres the girl has a looser design. The things that stick out to me in this piece are the poses of the characters, the girls dress, and the anatomy of the characters.
The poses of the characters could be pushed to be more dynamic/ interesting, an easy way to do this is to make the character have more angle and variation in thier stance and limbs, it makes it nice to look at.
The girls dress is mostly well done, but turns into a solid single line with the girls leg at the end of the line. To show the dress as taking up a 3d space it would be better to show the dress slightly overshooting the leg and then wraping around it to give it volume.
The characters all have perfectly straight limbs, to make it feel more believable try to have straights and curves on the insides and outsides of their limbs. It makes it much more anatomicaly correct.
The styling of the peice is well done, and I feel like you captured what you wanted to show, good work, keep practicing.