part 2
I think you should make the kids walk and fall speed fixed as well as the speed of the cart. instead make the distance between the kid and the edge of the building variable and the distance between the player character and the cart variable as well. Those two elements in addition to the different platforms (you can also make slippery platforms or sticky platforms) can give you more than enough to design interesting levels and create challenges that the players can enjoy and still feel in control (unlike the last level where you can only wait...).
good work, it has potential.