I like the concept, and especially that it can be played either carefully or by just wildly flailing both legs to fly up the stairs. Feel like there's a lot of potential for the level design to encourage both 'playstyles'.
To make it feel just a bit more like an uitglij bord, as an idea you could try making the legs collide with each other; maybe add some force to add yet another way to propel yourself forward. Not sure if the legs colliding would remove any other fun ways to move around, but might be worth testing :)