Overall this is very impressive! The side-scrolling effect is done very well as far as the level and player movement goes. A moving camera to my knowledge takes a lot more work to do in JS and I'm very impressed by your implementation. I would like to note that due to the nature of the way the good and bad data spawns in, and the way the player jumps (look into variable jump heights, like Mario and sonic games) it was difficult to avoid the bad data when trying to get the good data to score. I also encountered an error where a monster got stuck in the floor and I was unable to destroy him. I think some feedback that could be implemented is a special sound effect or more noticeable feedback when the player is invincible. After a little while I realized the player character did turn blue and the text in the top left appeared but I missed those initially so I think a sound effect would add a lot here. I think some type of progression would add to the game, like making the game harder the longer you play it, rather than just ending after you reach a certain score.
Please do not take my nit picks to heart. This is a very well done game, with good graphics, sound effects, player movement, and camera movement. As far as I can tell you are the only one who tried to implement a moving camera and you did it very well. All in all, great job!