That was pretty nice! There’s a lot of cool ideas in the mechanics, and the level-design is gratifying. I finished it in 1h30m, the estimated time is really accurate!
Some of the platforming felt a bit too punitive sometime (especially the Vault), but overall it was enjoyable. There was times I was afraid to not be sure where to go, but surprisingly wandering a bit randomly in the Park generally led me to something.
This makes me wonder how “linear” the level-design actually is? I always felt like I had several options, and there are even some paths I definitely never took. Are there different orders in which the game can be completed? Although I felt like I had to come back to Cistern way more than any other levels. But the global game felt very open while never getting me “stuck”. You did a very good job!
Small nit-pick though: it is possible at some points to get soft-lock! :p It happened to me twice, once by entering a room with the Ice with no ramp for exiting, and once by dropping in the Cistern with Glass. But given the scope of the game, it’s nearly impossible to avoid those kind of scenarios. Perhaps a “reset to previous checkpoint” action could help?