I am using macOS.
About the swapping of tapes, I admit that it was really fun to discover it and maybe I would have lost on that if you would have just explained it at the start, but I think that since it's so important to do it to even barely survive, some players might see the game, try a couple times and see that it is extremely hard and lose motivation to play because they didn't discover that. So I don't know, I think it's a risk but it might be a risk worth taking.
And about the telegraphing, you can for example lerp the sound down slowly, starting a second or 2 before the end, instead of just stopping when it's done. Or maybe also changing the ants on top of the machine. Or you could just do a small countdown like you said or a small bar.
And I repeat again something that I think is really important - make is quicker. I think you should make the player move more quickly, the tapes rewind more quickly, the customers come more quickly. If what you do in this game is walk around and rewinding tapes, why not do it a lot more?