Thank you for getting your hands on Sipho! :D
Noted these issues: skills activating on Dive UI button press, cancelling object placement issues.
Aquarium backgrounds and environments are dependent on selected breed - if you start with Advena, you'll get alien stuff and if you start with Cra'than you will get their fleshy environment. Changing background is not something we have planned to do, but we could, having enough interest from players.
We'll be further working on Aquarium UX - one video I've seen was enough to show how confusing the UI can get. If there are more "gotchas" you find in it, please let us know - it's very useful.
Our current plan is to allow sharing Sipho creations with others and implement a better management UI for them. Aquarium level management is not something we have considered, but least we can do is to expose Aquarium files (in a better way - they can be accessed right now in saved game files). You're right, there is nothing much to use to create shareable levels right now. If we ever add more environmental content, like hurtful obstacles, currents and other things that can make custom levels more interesting, this could be a development vector we could follow. Survival scenarios with hand-placed enemies and fixed awards could be interesting. But that could only come after current Aquarium polish and Campaign improvements we want to do.
Thank you for your interesting thoughts and feedback, I am always happy to read them.