This is probably my favorite entry so far. Primarily a puzzle game with some light combat/timing elements - imagine a Zelda game but with the ratio of fighting to puzzles inverted. The developer really nailed the puzzle side of this title; each stage introduces a new mechanic, first simply, then iterating on what you learned from the previous rooms, leading to a couple that really take thought. However, none of them feel cheap or like they were made uneccessarily complex to pad out the game time (which took me a satisfying half hour to beat)
Perhaps ironically, my favorite parts of the game was the fighting, used as a mechanic in one of the four stages and for the boss. The combat is designed in such a way that you can use the attacks and positioning logic of the enemies to create crossfires where they damage each other - or, you can rush in and brute force through them. This led to these encounters still matching the puzzle game feel, but with a degree of nonlinear solution that you can't normally get in a traditional puzzle scenario. Very well done
It's worth mentioning that all of this is done with an extremely elegant control system: 4-way WASD movement and two interaction buttons. Both main buttons serve dual purpose as attacks and puzzle-piece movers. There is a third button (a dodge) but I wound up never needing to use it, and the arrow keys are optional time-savers except in a couple must-use cases. There is a very fine degree of attention that was paid to building the character controller - input delays on the buttons are just right, if you hold a direction while pushing an object you'll continue to slide after it without having to lift and repress the direction input, and the use of the keyboard to incorporate the arrow keys for the occasions where precise control of facing was a good decision, I believe. This could easily incorporate a gamepad control scheme with a dpad, the four thumb buttons are the arrow keys, and triggers/bumpers for the main buttons
Other than the cut scenes, the graphics of the game work just fine, although I would say the music isn't the best fit. These are minor issues compared to the very engaging and polished experience present in Castle Colossus. I salute this developer - great work!