Except that the SatAM story continued in the Americanized Archie-produced Sonic comics...
And although Sonic X DID have some elements of the games in it (in terms of using the actual game characters), what turned me away was as follows...
1. The dubbing: To be blunt, the new American voice for Sonic sucks.
2. The human interaction: To my recollection, there were NO humans in ANY of the games, save Dr. Ivo "Eggman" Robotnik (formerly Jullian), so why include any other humans in the TV series?
3. The location changes: I mean, since when did Sonic live on Earth? His home is the planet Mobius!
4. The relationships between the Freedom Fighters: What is meant by this is that Sonic and Tails DON'T have that "brotherly" bond that they've shared in both the games & the previous TV series.
As to Underground, the thing that tuned me away from it was the lack of continuity, because it was NOT based on either the games OR the comics, and the show was completely random to the point that the creator's decided to give Sonic a sibling, even though it was proven that Sonic was an only child.
Next comes my rating for Adventures of Sonic the Hedgehog....Although it was silly like the games, I feel that the characters should've had more depth to them than the portrayals dealt with simply to appease the "kiddie" demographic.
In the end, I like SatAM the best out of the four shows, because though it was the one to have the least to do with the games, it had a well-thought out plot, keenly developed characters, and was the more "mature" out of the three series.
Not to mention that Jael White (who I can forgive for playing Steve Urkel on Family Matters) played a "way past cool" Sonic to near-perfection and the "brotherly" bond between everyone's "main hedgehog" and Miles "Tails" Prower was simply adorable. It was sickenly cute (for the sensitive people), but yet, tolerable enough so anyone can see the relationship there between the two friends.
Also, the show had a seriously amped-up and wicked awesome theme song: http://www.satamsonic.com/media/music/SatAM%20-%20Fastest%20Thing%20Alive.mp3.
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