I highly recommend against putting any real-time mechanics on "e". If the game had used the arrow keys, that'd be in a seemingly random spot on the keyboard. Since the game uses wasd, it's a really awkward button to press in the middle of a jump. Usually that'd be pressed with the index finger, but only because game characters usually don't need to move left or sidestep while interacting with static objects.
Also more generally, if the full game is going to have more such mechanics, I'd recommend at least having the option to use the arrow keys instead. That frees up the letter keys for more stuff that doesn't need to be pressed at the same time. (the other alternative, wasd + jk, etc. doesn't work on all keyboards)
Also, in-game text is only unprofessional if it's not given any thought to how it's displayed. I think there's a lot of games that could use more of it. In this case, it's a jam so not really a thing to worry about, but otherwise a simple wooden sign sprite behind the text would be enough in my opinion.