Wheres the landscape mode?

I have the iPhone 6+ and mount my phone sideways (landscape). I paid for this app only for that option, it doesnt work. You tap on the rotate button and the Zilla logo will rotate around, but the app itself does not.
Would like to rate this app better, but cant until they fix it.
I have also emailed the developer, but have had no response in two weeks.

jimpennjr0523 about Zilla: Digital Dashboard & HUD - The Ultimate In-Car Upgrade.