I know how it is to be a game dev on a deadline and have ideas of how to expand on a project, how it can be fixed or added to, etc. So please understand if I mention things you already want to fix or add.
1) Being able to choose the resolution and toggle the audio would have been a nice quality-of-life feature. I don't know if Unity allows for these settings to be toggled by default, or whether they have to be hard-coded in or not. This is just a minor presentation quibble
2) Selecting options with the mouse is easier than a cursor guided by arrow keys/WASD, but switching between keyboard (player control) and mouse (menu control) repeatedly is a bit cumbersome. This is just a minor presentation quibble, though if I had to keep restarting a level or keep going back to the menu to access the next level, in an upgraded version of this game, it would become annoying quickly
3) Either the jump height is a little too low, or the platforms are a little too far apart vertically. I keep knocking into the side of the platform I want to reach, and getting stuck/slowly sliding down. Then I hit 'jump' repeatedly to sort of climb up over the side. It would be a good learning exercise to study things like acceleration and deceleration, holding the jump button for a longer jump, buffering the player's 'jump' input before they touch the ground, etc. There's a good video with a slightly hyperbolic title on this subject.
4) Because I took a while to get used to the platforming, the first level was actually the hardest of the three! I kept falling off the bottom of the screen or not making it before time ran out. When I got used to 'climbing' platforms, all three levels were a breeze, thankfully.
5) Controlling two characters to reach a goal is a good pitch for this genre (the idea would work especially well with a gamepad, dual-stick control scheme) - and making the boy have to take a certain path is also a good idea. You've taken the core decisions the player has to make in platforming and added something to make them interesting but not convoluted. It gives the girl little to do by comparison, though. You've probably already thought of level designs where the platforms for both characters are separated from one another, strictly linear paths. Perhaps you could also make it so that certain platforms can only be landed on by one character or the other? (Platforms could start out as neutral until jumped on, then they change colour to signify who can stand on them.)
Whether you decide to expand on this game or move on to another project, it's a good start for a platformer.