I designed these levels incrementally. So, I started out with an idea in my head of how I want the player to solve a level and then just started building out from there. I then tried to add things to the level that make it harder to do another solution and I test to see if you can do it with another solution. This testing and building the level can honestly be quite time-consuming. For 1.5, I must've spent about 30+ minutes designing it.