Usability
Interface 
User-friendliness/complexity of the tool´s interface
Easy-to-use, straightforward.
Time efficiency Time needed for mastering the „how-to“ of the tool and a production of a task
High.
Interface language(s) The number of languages in which the tool is currently available/adaptable to
20+ languages.
Respect for privacy Does the tool require registration? Who can see my data? Can I remain anonymous?
High. Wordwall collects personal information such as activity title, first name, last name, email address, username, and password from teacher users. This information is collected to create and set up user accounts, create resources, share resources with other teachers, and assign them to students. For students, Wordwall collects data when users set assignments that collect the student' names and responses to questions. This is intended for educational purposes, helping teachers track student performance. Wordwall does not share or sell user data with third parties. It uses cookies to enhance user experience on the website. Concerning security, Wordwall securely stores user data on database servers operated by Microsoft (Azure), and all remote access is conducted over HTTPS, ensuring data is transmitted securely. It allows users to update or remove their account information by emailing the provided address. Wordwall complies with the GDPR. See more here.
Saving work for future use Possiblity to save your or others´ work for reuse/reproduction
Yes; login is required to save work.
Tailorability (If so, how?) Possibility of the tool to be used for a range of different activities (e.g. to what extent you can organize a project assignment with a central activity based on this tool)
Yes, users can customise activities to suit their needs.