This game's level design is genuinely so good. Almost every puzzle has a unique set-up and solving them relies much more on deducing your overall goals and how you'll need to reshape the available pieces, rather than the rote block shuffling or trial-and-erroring dead ends that many sokoban style games devolve into. Progression even through a single level is rewarding as each realisation clicks into place and leads you towards the complete solution. The difficulty is high but always fair; there are no obscure interactions to miss or meta shenanigans to worry about.
I strongly recommend purchasing The Golem if you are a veteran puzzle gamer. The only downsides are the lacklustre BGM loop (muteable) and the awkward 'hold to rewind' control that can fail to undo a single misstep if you tap the button too quickly.