It's hard to review a fighter based on a single video, especially from a display that majors in slow speed handling, but one or two things are immediately apparent. Most obvious is the quite remarkable ultra-high aoa handling that the Russians seem to do so well and have been for a long time - it clearly demonstrates LO's line about air combat manoeuvring. But more than that is the confidence they have in that handling to be doing it at low level, with a prototype. Roll and yaw control, even what looks like beyond 90 degrees is amazing although roll rates don't look that snappy at slow speed.
The other thing that is very clear is the SEP available, especially if those aren't the production engines. And that, in my opinion based only on the vid, is where there is a difference between T-50 and F-35, demonstrated in this video in two ways: the ability to accelerate in the vertical even at high aoa and the energy manoeuvrability available to be able to accelerate very rapidly from virtually stationary to conventional flight. Regaining energy does not appear to be an issue; again this points to LO's comment.
I think we did see an example of higher speed sustained g, but it's hard to guess at the parameters there. We also saw its ability to generate in excess of 90 degrees of pitch without simply stopping in the sky; nose authority like that wouldn't go amiss in a knife fight in a phone booth.
What the video doesn't show is off bore site weapons capability, how its acceleration continues at higher speeds, how additional weight affects what we saw there or whether it has any un-fighter-like g limits. I think I know the answers to those, but you only asked for comment on the vid.
Usual caveats about judging from videos and about any other platform and systems capabilities apply.