Technically, this entry isn't entirely true. I started watching the series by production order, not in the order that they aired. Not that it makes too much difference, because most of the episodes aired in the same order as their production listing.
Episode 1 of SatAM was actually the last episode aired of Season 1… which is odd, because it's clearly a pilot episode. Introduces all of the characters, explains the lore, has a design for Sally that isn't used anywhere else in the series… even its tone is clearly different.
Oh, it still has a more serious bend than Adventures of Sonic the Hedgehog, but you can tell that the writers hadn't quite found their footing in the atmosphere they wanted to convey.
I mean, when you have Buzzbombers getting taken out by (and running away from) water balloons, and a Hedgehog-Seeking Missile that looks like it was pulled straight out of Looney Tunes, then you can clearly tell, "Oh yeah, the team was clearly working out the kinks for this."
I know that the series isn't 100% dark, and has quite a few comedic moments later on (especially in Season 2, iirc), but goodness fuck, that's just zany.
…come to think of it, with its status as a clear pilot episode, it's easy to see why it aired at the end of the season, instead of the first. It had a better setup for the world and characters, but as an episode, "Sonic Boom" is a much stronger start for a series premiere.
Also, something else that stuck out to me that I did not remember at all: Robotnik very clearly beats the shit out of Snively at the end of the episode. Nothing's ever shown onscreen, but when you have a scene that ends with him going, "Snively… come here," followed by stars off-screen… yeah.
Animated series
Sonic the Hedgehog (1993) {S01E01}
ᴇɴᴅ ᴏғ ʟɪɴᴇ
"Snively… come here,"followed by stars off-screen… yeah.