The core gameplay is fun, especially if one has lots of emails unforwarded it could get frantic quickly. More types of emails could be added, for example one that requires multiple people to work on it.
A quality-of-life feature that could be added is the employees' progress bar so you could prepare to forward an email to them in advance.
There is a minor bug where an email would be generated on top of an existing one, so when selecting it there is a chance that the other one is selected instead.
With some work on the graphics and audio, this could be a very decent game. Keep it up.