The following image(s) is a little disconnected because I was not able to download the full photo. I instead took several screenshots, meaning the quality is also poor. It gets the point across, though.
Notes about this app poster:
The most important screens are shown at the top, with the exception of the first screen that only features the logo. It can be argued that the logo screen is important due to the absence of a logo elsewhere at the top of the poster. However, I think it would save valuable real estate if they just placed the logo rather than using a whole screen to show it.
Descriptions are short, sweet, and to the point. The screens are pretty self-explanatory. They save the Passably login screen until the very end to sort of bookend the presentation. The login screen is also completely pulled out, with no mockup whatsoever.
There are several instances where information is pulled out because another mockup is not necessary to show the feature.
They add visual interest to the poster by dividing sections with theme-colored shapes, as well as changing the color of the mockup cases.
They save space by inserting UI elements, such as the color palette, into the rest of the information. This way, you don't have to dedicate a whole section to UI Design elements.