Got it. I updated the watch app to display time in format based on the system settings - either 12 or 24 hours. The watch itself doesn't have these settings, so it uses settings defined on the connected phone. You would have to set it up on the phone (in settings) - after that Woo Screen app will start displaying time in chosen format automatically.
This change will come with the next release, hopefully in couple days. Look out for update v 0.73.
There is another change in the interface that I've been testing and will release now. If you enable GPS, the Jump screen will be displayed in reverse colors - white screen with black text. This is to easily differentiate between the Speed and Jump screens - red top on the Speed screen wasn't visible enough. I tested it on water and it works fine - black text on white background has the same visibility outdoors as white on black. Also removed red top background on Speed screen as it is no longer needed. White background will use more battery on amoled screens, but since it will only be used to display jumps for short periods of time (and display speed the rest of the time), the impact should be negligible. If GPS is disabled, there is no change - jump screen is still white on black.