AKarhu

Yes, and besides being permanent marking, it has no "backup sight" function whatsoever. In an unlikely situation of loosing the HUD while otherwise retaining mission capability, you can reproduce the HUD symbology on either DDI (two upper displays). This is good enough for guided weapons while all but useless for the gun of course.

In the Episode 1, Matt apparently referred to the M61A2 gun. I wonder which one it is in the simulation. Both versions have been installed in the worldwide fleet. The effective difference is only that the A2 is lightened, and in case of F/A-18, it moves CoG rearwards in comparison to A1 version. I am aware that early on this caused certain issues if flying with unloaded gun, leading into use of dummy "aluminum rounds" instead of flying with an empty magazine, but there were later rectified via FCS software update.

Yeah, as mentioned it is of a couple of uses, but is essentially a fixed "sight" to see where the HUD is aligned - the projected picture actually floats in optical infinity, and follows with you when moving your head around. If you look the HUD so that the cross and the dot are aligned, anything in the projected picture that is supposed to be straight forward is also aligned "behind" these printed marks. It is helpful if anything needs to be set referring to the airplane's axis. And as mentioned, it is not related to the helmet-mounted display, but found on every frame that I'm aware of, even if not equipped with, or from the era before the helmet-mounted display. To quickly see if an airframe is HMD-compatible, the small square box: ...is for the magnetic field based helmet position sensing.

I'd guess it is not size per se, but that the antennas were either or. I'd guess they could have reserved two locations to use two systems in one airplane, but likely saw that redundant.

I quickly found this brochure (link - PDF) for a similar transponder-based system. I actually had never met the term TLS before, back in air force tech all the mobile (or more properly, re-deployable perhaps) systems were just under the label TILS. On larger airfields so equipped, PAR was historically used around here (Finland) as a primary mean if ILS was not usable. I think not all the military airplanes had mode 3 back then, nor necessarily any kind of civilian transponders, as even the civilian ATC utilized military primary radar data in their picture. Transponder-based system would effectively replace both the ILS and the PAR if so wished. Of course, in case of Hornet, there were more...creative ways: I've been told that some guys were doing self-defined NDB approaches based on GPS fixes until they were told not to. :D One can also do a non-dependent radar approach using ground mapping mode and making a target to the end of the runway. They told me the fix on the HUD is actually quite stable and easily usable for this purpose.

And there also exist TILS schemes that are compatible with regular ILS system, in what comes to airborne receivers. The principle of function is entirely different it appears, though, and for obvious reasons when it comes to the the antenna array size typically required by the ILS. These TILS systems function by interrogating the standard Mode 3 Transponder, determining the relative direction to the aircrarft, and providing a synthesized localizer and glideslope signals that don't need to be that neat directionally. It of course follows that the flight crews using these must absolutely understand the function of the system, because the same "fake-ILS" signal is received by all the possible receivers. Imagine what that would do if you did have your standard autopilot approach mode armed out of habit and received the ILS picture meant for someone else perfectly on the beam...a perfect "what's-it-doing" really!

Not the worst solo either: h While not the best view on them, the high-alpha barrel rolls and the half-loop straight from the high-alpha pass are fairly impressive for this somewhat underrated airplane. And the same from the cockpit:

I believe the handle + pedal method relates to the fact that many Russian airplanes utilize pneumatic brakes, not having similar easy possibility for master cylinders at pedals as in hydraulic brakes.