Thank you very much!
T's Heartpower is definitely more on the technical side ^^
When it comes to hidden treasure, I'm planning to implement a way to detect hidden stuff later, kind of like Ms. Mowz in Paper Mario. For now the best way to know if there's anything left in an area is to look at the map discovery and treasure found percentages, in the map menu
I'll update the "somewhere nearby" text in the next update then! The hints you're looking for are in the same corridor as that puzzle (look near the top of the screen)
For the Cookie quest, you need to talk to Cookie while having 2 dopberries of each kind in your inventory! I'll also update the text to make it more clear, thank you ^^
As for Steam, the build is being reviewed! I was hoping I'd be able to release the game on both platforms at the same time, but it sadly wasn't possible. Live and learn I suppose, it should be happening soon, hopefully next week!
Thanks again, I'm glad you're enjoying the game! ^^