Process generally looks reasonably OK, but heres a few things I picked up:
1) Tamp: Probably dont need to tamp with that much force, looks like youre almost doing a handstand on the basket! Have you ever measured the pressure on a set of bathroom scales? Apart from that, the first tamp looks good, as does the last polish, but the stuff in between isnt really necessary. You dont need to polish with pressure (scrub?) as this is more likely to rip the surface, when the purpose of polishing is to seal the surface and prevent any coffee sticking to the tamper surface. BTW Id love to know what was happening off-camera!
Also be careful putting that much force on the basket when youre pushing on the spouts which are sitting on a glass chopping board. You could chip the board and get bits of glass in the coffee. I rest the edge of the portafilter on the corner of the bench with the spouts hanging over the edge. This is stronger, safer, and prevents any muck getting on the spouts and into the cup.
2) Preparation: Some top operators have apparently detected differences in taste between lock, insert cup, brew switch, espresso out, and lock, brew switch immediately, insert cup, espresso out - more chance of the coffee getting burnt sitting there next to the scalding showerscreen for several seconds. Just something to try; you normally have several seconds between when you hit the brew switch and when the espresso comes out which is enough; if its less than that the shot will probably be overextracted anyway. Also are your cups pre-heated?
3) Extraction: The shot looked too quick to me, in terms of its quantity, viscosity, colour (which is a little hard to pick admittedly), the speed of delivery and the resultant volume - when youre stirring it the cup looks close to half full and looks quite watery and after removing the spoon it just keeps spinning and spinning. Have you ever measured the volume youre getting? As a starting point it should be 60ml in 25-30 seconds. I timed about 3 seconds from the brew commencing to when the espresso started pouring, and on my Silvia that gives too fast a shot. About 5 seconds is about right from my recollection, so I normally know within 7 seconds of the brew switch going on whether Im likely to get a good shot or not. Try grinding a bit finer (Id suggest a firmer tamp but I dont think this is possible! :)). I imagine the espresso as it was would have tasted quite thin and on the bitter side, possibly leading to the requirement for...
4) Two sugars! :) Try the above and see if you still need sugar!
5) I start steaming with a full boiler rather than leaving the valve open for the first 30 seconds of the steam switch being on but either will work.
6) Milk volume looks about right, and a cold jug is good! Technique was a bit hard to see but after a while a good whirlpool seemed to develop. Not sure why you switched the steam switch off half way through though. Also, everything you did after pouring the milk, do before pouring the milk, i.e. turn the steam switch off, run the hot water switch with the steam valve open until you get water running out, close the steam valve, turn off the hot water switch and wipe the milk off the wand with a wet cloth. This cools the element from 135 degrees, refills the boiler and gets any milk off the inside and outside of the steam wand before its too dry. Your method will leave the super-heated element sitting there for up to a minute, which isnt as disastrous as not refilling the boiler at all, but the sooner you get the temp down the better.
7) Im no latte art expert but you can get better results holding the cup at an angle and getting the spout right down into the cup rather than pouring from up higher as youre doing.