Thanks! The jump button is made small for two reasons:
1. I made sure to not resize any of Kenney's assets. They're all kept at their original size.
2. Having to move over to where the button is is part of the challenge of that level. :D
Edit: Just to clarify on the above as someone else mentioned the concern, this is not to say your feedback is wrong, just to give context on why it was designed that way.