When Sega knew they had hit on their hands with the Sonic series they decided to take the same route Nintendo had done with Mario - basically to place their lead mascot in as many different games as possible. Mario crossed over to puzzle (Dr Mario), sports (Mario Golf) and racing (Mario Kart) games, and Sonic followed an near-indentical pattern. However, one of the first spin-offs (no pun intended) was this rather unusual fusion of pinball and platforming, which was at least slightly different to the output of Nintendo at the time.
Now on paper this actually sounds pretty good. Sonic is famed for speed, and he can roll up into a ball - perfect for a pinball game. However, the execution is depressingly sloppy. The game is annoyingly jerky and lacks the silky-smooth scrolling of Alien Crush (also available on the Virtual Console). The ball physics are unconvincing and the platforming elements only serve to frustrate - they're a long way from the original Sonic platform games in terms of quality. This is most likely because the game was coded in the US and not by the original development team.
This is a brave attempt, but unfortunately it just comes across as a bad platform game and a bad pinball game stuck together. I'm sure the fact that Sonic is featured will tempt a fair few people to download this, but my advice would be to stick with Alien Crush, which is far superior game in pretty much every respect.