This shot shows that the fan face is visible.
(Note, full size pic is humongous)
Detail of inlet
A variable geometry radar blocking technology.
Russian with subtitles
A useful PowerPoint from public sources
In terms of the development of the aircraft, it appears that both the Salut and United Engine Corp. (UEC) will work jointly to develop the a 2ndproduction engine for the aircraft, (paid subscription required) in addition to the engine being developed by Saturn, the prototype is flying with a variant of Saturn’s AL-31-F.
This indicates I think that the Russians are placing a lot of importance on the timely service entry of this aircraft, and I think is a far more sensible course of action than the jihad the Pentagon has had against the F136 alternate engine for the JSF, which may lower development costs in the near term, but almost certainly raises costs, and risks in the longer term.
As to stealth, it’s clear from the top two pictures that the engine fan face is clearly visible from a fairly wide (15°+) angle, which implies that some sort of radar blocker must be present. (H/t whoever posted them online)
If you look at the first video (3rd item on right), it looks like they may have a variable geometry radar blocker, which would provide a helical path for air, and signal, under some circumstances, non-maneuvering subsonic CAP, for example, and would provide a straight path when more airflow is desired, such as during a dogfight or supercruise.
Additionally, the bottom video lets drop an interesting manufacturing technology at about 2:25.
The fixtures for composite construction that that they are using have a very different philosophy than those used with US aircraft.
With US aircraft, Invar, which has a low coefficient of expansion, is used, where the Russians are going with tooling that is made from the same composite that is used on the airframe, so it will expand and contract with the underlying structure during the autoclaving process.
I just find this interesting as an engineer.
H/t Bill Sweetman for both vids.
Finally, there is a PowerPoint, h/t Stephen Trimble, which assembles most of the publicly available data on the PAK-FA, and serves to paint a rather more complete picture of the program and its capabilities.