Really challenging and addicting! It took me awhile but I did end up beating it.
You've done a very good job with the movement. The walljumps and dashes feel very smooth and the movement overall has a good sense of weight to it. Also the level transition visuals were a nice touch.
One thing I think could be improved on is the length of time between retries. Sometimes it felt a bit frustrating to die at a part over and over, especially when it was near the end as I would have to wait for the screen to scroll all the way back. Which on its own isn't very long, but this adds up over a number of retries.
Overall, this was a really solid 2D platformer. Well done!