I am not sure I can clearly see the difference in performance between the two videos that you posted. Perhaps the first one has more abrupt flow, a staggered frame rate, this is what you describe as jagged. I don't see any blur though. I am confident that between the video capture software and the youtube decoding, some information is lost and that you see more of this problem than I do.
Now, first of all I should say that Construct 2 does have an issue with occasional staggering. It is described on other posts, basically, it looks like every few seconds a frame or two are being dropped and as a result the movement losses its continuity. It's a subtle, but evident effect that I wish it wasn't there.
In your case, I wonder if you use the Platform Behavior in conjunction with the 8directional Behavior...? If yes, when you walk and jump around in the platforming section of your game, do you have the 8directional Behavior deactivated? If not, perhaps there is some conflict between the 2 behaviors and that is causing the jagginess...
I can't think of something else for now, if you like you can attach your capx file for the rest of us to see and check if there is some error from your part and/or if we experience the same problem as you do.