Your game was made almost one year ago; my comment wouldn't be very useful then. But great game! Wow, it's so cute! For that, I would change one detail. I would keep the home as it is but make grandma, gone on vacation, appear on a computer screen on a wall; worried about her cats; trying to open the door for them with the use of a small toydrone. It would just replace the ghost sprite with a minidrone sprite and the gameplay would be the same. You can even transform the small appartment into a big house, with one computer screen in each room (grandma loves to watch her cats); each room being one level; it adds alot of potential until the last exit but also alot of work. And poor fish, why not send some cat food on the stove instead; the cat would leave the fish in peace at the same time. Like this we have one happy grandma, cats and fish >^.^<
Actualy I think the death is a nice part of the game. It had kinda become a taboo subject, like if death was something horrible that we must absolutely not think about or be super afraid by it. But death is just part of life. Here we have the story of a nice grandma who, once her time has come, make sure that the creature she love are safe and then go in peace. And this is adorable, there is no need to transform the story to remove the part that show a peacfull and 'happy' death just to preserve the taboo. I wish we were exposed to more of these kind of 'gentle' death in our current media.