To advance past this screen you must click More info and then Run anyway on the blue screen.
On Linux platforms such as Ubuntu and Fedora, Arctype is distributed as an AppImage. This provides a number of benefits, including easy updates with improvements and bug fixes. However, AppImage files are distributed without the execute bit set. This means you must run chmod +x Arctype.AppImage after you install it.
Or, you must right click on the on the file, select Properties then Permissions then check the box for Allow executing file as program. Then you can double click on the icon to run Arctype!
On MacOS you will see a message saying This application has been downloaded from the internet - are you sure you want to open it?when you try to run Arctype. You must right click on the application and select 'Open' to run it. You only have to do this once.