I actually didn't mind the hints having ambiguity; by allowing the player to make the idea-to-input connection themselves, it gives the physical simulation of the photo development more impact. However, the very first one (wrap the film around the spool) required precise timing so it was difficult to get feedback that I was providing the correct inputs, especially before figuring out it was meant to be simultaneous and not a sequence. (Personally, I think a cool spool input would be: hold Z, press Left to spin it a little, press Left to spin again, and so on, until it's wrapped. Although, this would likely have the same problem without more explicit hinting.)
After this though, the ambiguity is just fine, and even rewarding like in the wash basin for the shake/swirl actions, the player is probably expecting a simultaneous input but instead is treated to something new and delightfully interactive.
The way this game made me feel is difficult to describe. I'm engrossed in the story depicted, and at the same time, it brings forth my own memories of dropping off film at the local photo lab. Reinforced by the soundtrack and red palette, it evokes nostalgia, slightly tinged with pathos. Maybe the exact quality is different for everyone, but it's hard to imagine that the game doesn't send a player down their own memory lane.