I also have a hard time balancing the difficulty in my games. I made it only to the third screen, I was not using the checkpoint system properly and think thats why i had such a hard time. i think if you added an in game way to showcase the different abilities like the dash, by forcing the player to use it to progress it would help a lot with understanding where and when to use it. I think if the spikes were more visually distinct, they would be less frustrating. Also i think the character needs more visual and audio feedback to make basic movement more satisfying, it go a long way in making moment to moment game play more fun :D