Sonic 1 secrets for the achievements

I was wondering where 2 of the secrets mentioned in the achievements section were. To be honest, I tried but couldn't find anything for the Labyrinth Zone act 1 secret. I might have missed it as it is small. If I'm not mistaken, if you go down and activate the platform that goes up into the spike (the left one) from below the area in the screenshot below and climb back up, you get to unlock this small little platform that can hardly be noticed even if it's in front of you.

In the below picture, it's above the pole closer to you.

And it moves to the secret area to the right... The below picture shows it much clearer with it visibly above the waters.

Then there is the Scrap Brain zone secret transporter. I didn't have a clue at all as to what it was so I searched and found this video which shows 2 secrets in act 2, the first being the 50 rings transporter and the other being that secret disappearing platforms that you need to know is even there.



And I also found out, to my horror, that Knuckles can't jump as high as Sonic or Tails!!!

If you want to know the secret area of marble zone 3, it is at where there are 2 of those spiky dropping platforms with the chains pulling them up. There is a hole in the wall. Alternatively, you can enter from the other side which is under the spikey dropping platform,to the left wall, directly under the area where you need to hop across to get to the outside before the boss.

The game actually has quite many secret areas. Like under zone 2 of Green Hill Zone which I have no idea how my dad had the idea to jump past the first spikes down years ago. LOL!