This was made to show how you can make decent level design, while still keeping it simple. This is by no means great level design, but I feel that it greatly improves upon the base levels that were created by @SwaeScratch The things that have been added are spikes, and a few extensions to the ground in some places. I noticed that the game had a lot of levels based around stairs, so you may want to change that, but if you don't change it, I would recommend adding something unique to each one.
This is not meant to be hurtful in any way, and was simply created to help the creator find some different ways that they could modify their existing levels to make the game have better level design.