I would personally throw the first 3 enemies that teach each button of the game respectively: A, S and D. Then I would start to throw them randomly. I would remove the signs and poles which inform the player about the key and the time they should press a button, since it is the main killer of the game as I mentioned. And to give the ability back to player to make a decision and react to enemies, I would slow down the enemies speed.
Ok that makes sense, thanks again! at first I didn't have the poles to indicate where to jump, but after a bit of play testing people were having trouble determining where to jump from, so I put them in as an indicator. I do like the idea of having no indicators after a little warmup but the way the game is set up, it isn't really a viable option to remove them and have a slower enemy speed :( Thanks again for the feedback!