The Cave is an okay game. Not nearly as good as Seasons, which is their masterpiece. What's definitely missing is one of those 'what the hell is going on?!' moments like the ones in Birthday and Arles.
Sometimes it's okay to consult a video walkthrough!
https://www.youtube.com/watch?v=d80AQGv7BfE Part I
https://www.youtube.com/watch?v=mCkc-nMAKa4 Part II
Other Rusty Lake Games I've played/reviewed:
Cube Escape: Birthday
Cube Escape: Case 23
Cube Escape: The Mill
Cube Escape: Harvey's Room
Cube Escape: The Lake
Cube Escape: Arles
Cube Escape: Seasons
Cube Escape: Theater