So i actually managed to pass through the first three stages (RUINS I, RUINS II, RUINS III) in the Caveboy Escape Game after playing the 900 levels (3 stages x 100 levels x 3 puzzles per levels) in order to unlock the stage Forest I.
previous Walkthrough, the challenges onwards are 95% similar. In the Forest I stage, you are still going to help the caveboy escape. Except the fact that, in the third puzzle of each level, you need to locate the key first before entering the destination. Yep, the difficulty added is that, the key may not be on your paths to the exit. In some cases, you have to purposely take a longer path to reach the key first before returning to the exact exit paths. Other than that, there isn't much difference.
Ohya, you may argue that the tiles in the FOREST I stage are having closer colors (eg: more greenish). That is 'slightly' more difficult to play with. But overall it is still fine.
Again, there isn't a need to use the potion to solve the puzzles. Reverse engineering would pretty much solve every level. I would stop here unless you wish to know some solutions to get the 3 stars.
What i really wish is, the developers could reduce the similar puzzles, and add more variations into the game play (eg: add spikes or obstacles or sth). Let's wait for any update soon.