As Dinius is rubbish and doesn't seem to brag about his new videos.  I noticed the ProjectRIK Youtube has a new video.  Pretty enjoyable to watch IMHO.https://www.youtube.com/watch?v=MWosSwPXkls
Need to figure out how to make actual smooth videos though, they're all somewhat laggy :P
60fps would help! :D
I thought the local file was, but was an old file from like a month ago so I could be wrong. But was thinking more generally, there are videos out there that are perfectly smooth at 30 or whatever youtube used to have, while the RIK videos I've upped aren't nearly as smooth as the local versions. 60fps or not :P
The only way to get a smooth 30fps video is to use lots of motion blur, but with 60fps it's a lot less necessary - it's more of a stylistic thing at higher frame-rates. I don't know if your game has the proper features to capture at high fps to resample (and have the resampled footage look good), or simply do motion blur on its own, but if it doesn't then you won't be able to get the smoothness at low fps that requires motion blurring.
Youtube video
ca 3:40, no motion blur to speak of. Perfectly stable\smooth. Not 60fps smooth, but no jittering or whatever you want to call it, which you can notice quite a lot of in the RIK videos here and there, even at 60fps. But the local files doesn't have that. Anyways, I think I've figured it out, so no worries :)
What was it? Because I can't think of anything other than it's just w3sp's movement being really smooth; I don't see anything really wrong with the video in the OP.
It's not about the movement as such, it's a combination of..
  • Encoding settings 
  • Encoding settings vs youtube
  • How the clip was actually made ('avidemo' vs direct to video, recorded otherwise, etc..)
And ofc, as you say, motion blur can be added to that, but laggy playback would still be laggy to some extent with motion blur as well.
Will post up more info on this later on when I've actually tested every scenario and am 100% sure :p
I enjoyed the video ALLOT, really great starting instrumental!! Can I has plz? :p
And ofc a really nice smooth run be it for one interruption :D
Image
 
Mush as in from ET ooor?
LoL! And yes! Hi :)
f33l had no motion blur iirc, the xvid originally was 1280*800 @ 50fps, but youtube converted it to 480p @ 25fps.
Same run amateurishly compiled at 720p @ 60fps with motion blur:
Youtube video
Additionally:
While the majority of the f33l content was online demos, for the capturing process of the movie they were heavily smoothed using gaz tools to basically make them as good as an offline demo (adding and interpolating missing frames, etc...)
Makes sense :) 
All demos I've used here are local though, and so forth. The local files etc are perfectly smooth, it's the encoding process that disagrees with it to some extent :(
I believe if you record and upload in what youtube considers to be HD (720, 1080, etc), and also at 60fps, then youtube won't chop it down to 30fps anymore. This is a relatively new feature. A lot of fighting games are using it now, since they all run at 60fps.
I tried recording this at 1080/60fps, do you consider it smoother?
It's not about the smoothness itself, it's more about the "consistency". Or rather, small lags\stutters, your video has lots of them. I don't have them in my local files, but they appear when I upload to youtube. Haven't found a 100% solution yet. Playback will be fine in Internet Explorer for example, but chrome and firefox both get these stutters.
Apparently it's only working in chrome (and IE) right now anyway. If you load the video I linked in those browsers then 720/1080 quality options become 720/60fps and 1080/60fps. The difference is noticeable.
It's not about the 60fps. YES, the 60fps is smoother and better, naturally.
But what I'm on to here is the small stuttering and laggyness you get at times in the video, that DOESN'T exist in the local files before upload. From googling some while back it's somewhat a common problem, dunno how to get around it completely, seems to be youtube's fault from what I can see.
You can clearly see it in your video too, even if you pre buffer the whole thing so internet connectivity isn't the issue either.