iKwak, I managed to download your file no problem.
Here's how I would duplicate the effect:
1) Open two video tracks
2) On the lower track, place the video event you want to use.
3) Select the event, hit CTRL + C to copy it.
4) Go to the upper track and hit CTRL + V to paste the copy on that track.
5) Lower the opacity of the upper track to about 50%. You can change this to suit yourself, but for now you need to be able to see the lower event in addition to the upper event.
6) Line the events up so that they start at the exact same time.
7) Then nudge the upper event a few frames to the left or right...say, 3 - 5 frames to start with.
Then watch your video to see if 1) lowering or raising the opacity, and / or 2) moving the upper event a frame or two to the left or right gives you the exact effect you want.