Knuckles in Puppet Panic Act 1 is impossible to get to, same for Tails in Act 2. As such the game is impossible to 100%
SPOILERS:
Panic Puppet Act 1 Knuckles Location: https://cdn.discordapp.com/attachments/315258983399161866/382711815442006016/unknown.png
Panic Puppet Act 2 Tails Location: https://cdn.discordapp.com/attachments/315258983399161866/382713017671876618/unknown.png
https://cdn.discordapp.com/attachments/315258983399161866/382713094675365890/unknown.png