Nice job. Good to see someone else posting a game made with UE. =]
Some nice background music and a jump sound effect would fill in some of the audio 'gaps'. Also, the jump input felt delayed or occasionally didn't work at all.
I'd actually prefer if the game play was in in 3D instead of a side-scroller. There's also an old endless runner tutorial for UE4 on YouTube that shows how to generate random tiles in 3D as the runner progresses if you're interested.