>>105
Boosting would have been fine if it didn't end up an effectively limitless resource in most games it appeared in.
I liked it in Unleashed considering how you actually had to make sure it didn't run out.
An infinite source of invulnerability that speeds you up and also kills enemies is a bit too strong.
I like the idea of Sonic being able to boost, but I don't think it should overshadow the other things he should do.
Perhaps if it were a pickup or SA style upgrade with limited use it would have worked better.