First off, I want to mention that I really like the form factor of your game (no sarcasm - fuck standardized width/height ratios right?). You have no music, which is somewhat sad, but you do have screenshake, sounds, and nice sprites, which totally make up for it. I like the graphic style you went for. The game feel was definitely there, altough you might want to tune down the general game speed a bit - it felt kinda twitchy to me (it ran waayyyy too fast, maybe it's because my pc is kinda fast? You should make your game behave properly regardless of framerate). All in all a sweet looking entry!
Great platforming physics implementation, variable height jump is there, feels responsive. The scrolling background made my eyes hurt after a bit, and I think you should just do translation for screenshake instead of rotation - its a standard technique which in my opinion feels much better. Good entry though, I enjoyed playing it!
I don't know why you got a virus warning, it's a GM:S Original license game.