As others pointed out, it really would depend on whatever media you refer to: Sonic has multiple "canon" universes, so one should at least specify what series we would take as the main reference point.
Starting with the Western Animated Shows adaptations:
Adventures of Sonic the Hedgehog (the one most will remember) was very loosely based on the games and while it managed to keep the original art style to a point, it was mainly focused on humor and jokes. This show seem to give the idea that Robotnik is one of the few humans (if not the only one) living in Sonic world. As far as technology goes, the world seem to have some, but it is most limited to what the plot needs, with no sign of major advancements. Even Eggman doesn't seem really advanced in this one.
Things change in the somehow darker adaptation usually called "Sonic SatAM". Here, Robotnik is basically an evil overlord that is trying to turn all the inhabitants of the world (Moebius - same name used in the original Sonic game) into robot slaves. In this series, almost all the technology is in Robotnik's hands, but there are some exceptions (Sally portable computer begin the one I remember mostly, the power ring generator begin another remarkable one). Anyway, the main theme was a sort of "nature against mad machine empire", so it is pretty obvious to think that people on this Moebius don't really rely on technology much.
I can't really say much on Sonic Underground since I never saw it - it somehow resembles the premises of Sonic SatAM, but this time there seems to be more technology elements in the hands of the "good side". Sonic has anti-gravity shoes, Sonia uses a motorcycle and so on. Still, I don't think that there is any major indication of a widespread technology usage other than some sporadic "artifacts".
As for the Japanese/Anime shows adaptations, we can skip them for now as they mainly follow the games they are based on (Sonic CD, Sonic Adventure 1&2 and Sonic Boom) as far as the general "world background" goes. Same can be said about the comic adaptations, which seem to follow Sonic SatAM and Sonic Underground mostly.
So, let's now just consider the games. Sadly, things get even more confused.
the original Sonic the Hedgehog game doesn't really give any real indication. Sonic it said to live on "Mobius" (which some still argue if it was originally intended as the name of the planet or just the island we see on the game level map). Plot is also very basic: Robotnik is trying to conquer the world, using animals to power up his evil robots. We can only assume that, as for Sonic SatAM, this is another "nature VS machine" scenario, with all of the technology on Robotnik's side. This is somehow reinforced by the good ending of the game, where the six chaos emerald are used to revert Moebius to its original state: the island map is cleansed of Robotnik's structures, which also seem to be the only advanced ones.
later games seem to maintain the same formula for a while - Sonic 2, Sonic 3 & Knuckles, Sonic CD all seem to point to the same "natural world with evil technology based villain" formula we have seen so far. It would be really nice to know how Robotnik was able to build some of the most extensive structures "by himself" in the first place (even with a robot army at his command, if he is to be considered the source of all technology that means he managed to build things like Scrap Brain, Oil Ocean, the Chemical Zone and so on "single handed") but we probably won't ever know.
then, the Sonic Adventure games came... and things got weird.
- From Sonic Adventure 1, the original islands seen in the first games seem to become small man-untouched dots on a world populated by humans. It isn't really clear if the games are meant to follow the same premise of the Sonic X game (Sonic&Pals are thrown in another world by an incident with the Chaos Emeralds), but what really matters is that now Sonic and his friends are anthropomorphic animals in a world where humans seem to be the main species. Technology level seem to be on-par with our current developments, with the usual video game stuff thrown in (flying windmills in Wind Valley? A highway with loops? Casinos with flippers where you are the ball??).
- Sonic Adventure 2 pursues the same road, but the world is progressively getting more advanced - the Gun soldiers seem to have a pretty high level tech on their hand, and the space colony "Ark" doesn't seem to be considered out of place.
- Shadow the Hedgehog then throws whatever logic was left out of the window. Now aliens are involved, the game has hoverboards, guns, tanks, Gun uses powered/mach-like armors and so on.
- Sonic The Hedgehog 2006... never happened, so I will gladly skip it.
- Most recents games again seem to focus on a "Sonic&Pals VS Robotnik" theme, leaving the rest of the world out of the picture (probably due to the poor reception some odd plot choices involving princesses had...) and we are slowly returning to the "animal world with Robotnik using technology to conquer it" scenario.
- Sonic Boom follows this road, with a general "as advanced as plot requires" scenario (the inhabitant of the world seem to have mining machines and canned food for example) with Robotnik and Tails begin the main tech based characters. Still, it doesn't seem that the world can be considered an advanced one (at least, I didn't see any Light armor capsule lingering around the levels...)
I know this only scratches the surface of this question, but I fear a complete analysis would be probably worth a full book, so I will cut this here. There are some curve ball here and here (Sonic Rush had submarines, Sonic Riders: Zero Gravity seems to imply that hover-board racing is normal and don't get me started on Chronicles), but the general idea I have is that the world isn't generally meant to be really advanced, with Robotnik begin the odd apple that somehow has access to more futuristic tech.
I'm going to assume that you're talking about the original 1991 Sonic The Hedgehog game and you're simply asking if, in that world, does Dr Ivo Robotnik (Dr Eggman in the Japanese version) have technology so advanced that nobody else has even conceived of it?
In short, the answer is yes.
The original game is set in the "modern day", which means in 1991 in this case. It is also set on Earth, somewhere called "South Island", which I can only imagine is somewhere in the South Pacific. Dr Robotnik decides he wants the Chaos Emeralds and knows they're somewhere on the island. In order to find it, he uses his 300 IQ intellect (Yes, you read that right, his IQ is 300, higher than any recorded human's) to slowly convert the animals on the island into robots, kind of like Cybermen in Doctor Who. These Robo-Animals then search the island for the Chaos Emeralds.
To do what he did in 1991 would be impossible for anybody other than him. It's still impossible in 2016. Building a robot is one thing, but converting a flesh and bone creature INTO a robot? That's crazy. AND he has these incredible machines that are insanely efficient, powerful yet lightweight, some of which are able to fly, which I'm pretty sure don't obey the laws of physics as we understand them.
So to answer your main question, yes, in that game his technology is certainly unique to him, but 50 years on, somewhere around 2041, I reckon we'll catch up.