Thank you for the comment!
I'm not sure if I hear the same thing you do but I also felt that one synth I used felt a bit "off" (not necessarily in a bad way) but in the end decided to keep it in because if cats were to sing they wouldn't be flawless, though maybe it might have been a bad idea from me xD
I haven't listened to a lot of Sonic music but guess I'll have to listen more. I think the use of mixing pure sin/saw waves in the lead with a more modern sound might be the reason why it reminds you of megadrive. Since I work mainly in midi using electric guitars will never sound real so I think by mixing that sound with other more "acceptable fake sounds" the resulting sound feels convincing.
Thank you for the feedback!