What the hell?))) Why I see only Season 3, where is 1-2? I want to watch this from the start))

So I just bought this bundle of 51 episodes and thought that I'd educate myself in the fine art of Gintama. Turned on Steam link on the TV and went to videos... The result was that a pile of 51 episode names was presented as a single garbled puke. How the heck am I supposed to find something like "Season 1, Episode 1" from nothing but the text names of that many episodes? After pressing play it does actually say what season and episode it is. How very convenient. The topmost entry in the list turned out t...

OC commercial!

Basically, there is an assumption that any games I buy on steam, I have forever or as long as steam is in business. I'm not sure how that works with videos though. firstly, can I download these just like I do with games. secondly, how long will they be available on steam? If I buy tomorrow, will thye be mine forever? or will steam quit their license deal at some point and lose the ability to give me the show I paid for?...

So, how is the video quality? BD-like or Crunchyroll's compressed 1080P-like?