Scores

What I played

Tidekeeper, Spring Tide (the hardest level). Before changing anything I released the tide. The castle washed away, one fish drained dry and a crab ended up trapped. The V preview showed the tide getting into the octopus basin through the cell next to the castle. When I piled that cell first, the game refused: "Your bucket is empty. Dig somewhere first." So I dug the basin's new inlet at (5,4) down to 3 and then piled the castle's side. That fixed the castle, octopus and upper fish, but the lower fish was still dry and a crab was still wet. Two more scoops finished it: dig (5,7) so the crab drains through its neighbour, then pile the drain at (3,8). The crabs now drain into the fish pool at exactly the fish's depth, and everything passed. I also worked through Deep Water and Corner Cases on paper. Each has one clean idea: build a new wall inward, and seal a gap diagonally. No JS errors.
Backstitch, Dragonfly (the hardest level) and Cross Stitch Heart. On Dragonfly I tried laying a \ leg first and got a clear layering error. I then wandered down the body until the hint said "Dead end... Undo 5 stitches (marked red)". I solved it at par for the star. On Heart the reach circle and "Too far" feedback were clear. Legal holes are ringed, which helps, but it also turns play into following the rings. No JS errors. The solver shows most levels are very loose. Heart has 51,819 solutions and all of them meet par, so par adds nothing there.

Reasoning

Tidekeeper is the more fun game to play right now. Its rules are physical and intuitive ("water fills to the lowest rim"), each puzzle takes 2 to 4 meaningful scoops, and releasing the tide is a moment of truth like Snakebird's. The water rises, the castle crumbles or stands, the creatures react, and verdict bubbles show exactly what went wrong. Spring Tide gave me a real layered "aha": dig to fund the pile, move the door, and let the crabs drain through each other. Backstitch is the fresher idea, and its two-sided thread is genuinely novel and beautifully rendered. However, it asks a new player to take in a large stack of rules: alternation, no straight return, the reach circle, coming up only where a stitch waits, hiding behind lines whether sewn or not, one thread per line, and leg layering. Its early levels are so loose that they mostly amount to tracing a route. Solving it feels more like carefully clicking through 28 holes than a sudden insight, and on organza the back view can't be told apart from the front. Tidekeeper's weak spots are small scoop counts, a roughly 6-second tide wait (Space hurries it) and an oblique view that can hide pits. Its list of physical mechanics (tide tables, rain, springs, sluice gates, multi-day beaches) looks more likely to keep me playing for hours.