One feature request: Using the keyboard you can change the zoom level in steps of at least 10%. 10% steps using the arrow keys and 30% steps using the Page Up/Page Down keys.
It would be fine to add a keyboard modifier - Shift f.i - to change the zoom level in 1 % steps. So if you press Shift - Arrow Up, the zoom level is decreased by one, and pressing Arrow, the Zoom level is decreased by ten.
Btw: It is sometimes impossible to change the zoom level using the mouse to 80%, 90, 100% ... percent. It changes from 99 to 101 and from 89 to 91. The workaround is to use the shortcut "100%"