Wow, in less than a week, that shows a lot of dedication and is a gigantic compliment :)
Did you collect the secret ability and did you use the secret behind the 99 door?
Most Metroidvania games have a set order because you need specific abilities to progress.
But what many people didn't realise, in the second third my game becomes a bit open-world. You can choose if you want to begin with the vulcano or the mine after that you can choose to do the security area or the other temple or the sandcastle and you don't have to finish the security area you can wait until you have all 8 cubes or do it whenever you want. Or you could start the mine play halfway through it and then go to the vulcano. Most likely I wouldn't do that again because designing it gave me severe headaches and confused some players, so it wasn't worth it.
But I know what you mean, in most cases only one room leads to the goal. Especially the first third is a bit linear. It's because I wanted to give the feeling of progress on your way home and I know that western players prefer to go from left to right , thats why Mario always does it.
But if I would ever make Bobo The Cat 2 (might happen) I would approach many things differently because it would be boring otherwise.
After work I will patch your name into the game. I will tell you when the new version is online.
Thank you for your detailed reply :)