I remember watching this when I was a kid. It was on Channel 4, Sunday at 9am and I used to watch the programs for about two hours beforehand so I would be sure not to miss it. Is it really that good? It was to me, and still is.
People comment that the humour is very slapstick in this. They're right. But so what? Pantomime is slapstick and nobody complains. Why? Because it's an accepted part of the show. I think the same goes for this one.
Is it better than Sonic X? Tough one. I'm a huge fan of Sonic X (mostly because I happen to be a huge fan of Knuckles, although I do love the series for its own sake). I don't see how you can reasonably compare the two of them; Sonic X is good for older viewers, while the slightly younger ones will probably enjoy this one more. The one thing that bugs me a little that I don't remember bugging me when I was younger (the age thing again) was the way that occasional episodes would ram the moral down your throat. Example: in Subterranean Sonic, after Sonic and Tails rescue the miser mole, he turns to them and says something like, "Oh, I can't thank you enough for showing me the error of my ways!" and then the three of them walk into the sunset together. Corny? You betcha. But so what? These incidents are few and far between, and if you're too old to be affected by them, you're not too old to laugh.
People who slam this are most likely used to the straighter story lines of Sonic X or can't remember what it was like to be eight or nine years old and watching this. No, it doesn't have particularly deep or engaging story lines. But since when does a twenty minute cartoon for kids really need them? On a closing note, it features the ultimate Robotnik. Long John Baldry's voice was absolutely perfect for this character; it's such a shame he wasn't able to participate in any other Sonic productions.
Bottom line; it's great. I doubt it'll get you on the edge of your seat unless you're aged about ten or under, but Sonic fans can still enjoy it.
