Absolute masterpiece of a puzzle game with a captivating and intriguing narrative. Everytime you think you've finished the game, they pull you back in. I cried the first two endings as the characters really grew on me. Not a walk in the park, but as long as you keep going, you will progress.
You may want to create notes for some overarching puzzles.
This is the 1st(ranger) game in the Ranger series, the 0th game being Zero Ranger. Having context of the previous game isn't required, as I did not, but it does provide a few clues to what's going on, and probably more questions. Also I'm not sure the "St-Ranger" is intentional... but I adore the idea.
As a last result, there are guides for most of puzzles, and an entire playthrough documented, I do not think you should be ashamed of using it when you get stuck. But also... I think it's fine to take long breaks. Hop back into the game every once in a while, take a crack at it, at your own pace.