Eunyong1002's questions and help with autoscrolling shmup

Link to eunyong1002's unanswered questions: help-with-a-auto-scrolling-game_p820039?#p820039

I'm making an auto-scrolling shoot-em-up (without the shooting). Problem includes a slight jitter/shaking of the screen.

I've tried slowing the player down, slowing the screen scroll, and deleting objects, but the jitter persists.

Using Windows Vista, Firefox 33.0.2, Construct 186.2 (64-bit).

Capx: https://www.dropbox.com/s/0ezbcxrlyk28y ... .capx?dl=0