Gamification is widely used in various domains as it helps increase user motivation and engagement. Therefore, it is important to ensure that the gamified system meets usability requirements and conforms to user experience and human-centred design guidelines, as poor usability may lead to undesired side-effects, such as a loss of user retention. Unfortunately, it is not entirely clear what usability guidelines are related to gamified systems and how they depend on the gamification target audience and on the gamified system application domain. This paper provides a systematic review of usability, user experience and human-centred design guidelines for gamified systems. A systematic search was performed in Web of Science, Scopus, IEEE Xplore, ScienceDirect, and ACM Digital Library databases, following the PRISMA guidelines. The results show that most of the recommendations listed in analysed papers are related to improving learnability of gamified systems. Furthermore, the system application domain is generally viewed as very important when making usability-related decisions. The key distinctive gamification application domains are medicine, education, and business. The findings may be useful to usability and gamification researchers, as well as the developers and owners of gamified systems who want to grasp the state of research into the specifics of gamified systems usability.

Publisher: Vilnius University Institute of Data Science and Digital Technologies, Journal: Informatica, Title: Repository for Business Rules Based IS Requirements, Authors: Kęstutis Kapočius, Rimantas Butleris , The quality of software engineering projects often suffers due to the large gap between the way stakeholders present their requirements and the way analysts capture and express those requirements. With this problem in mind the new method for business rules driven IS requirements specification has been developed. In this paper the architecture of the requirements repository, which is at the core of the proposed method, is presented. The repository model supports the storage and management of all components of the captured requirements, including functions, business decisions, data sources, conceptual data model elements, business rules and their templates. The important aspects of the specialised requirements specification tool implementation are also overviewed.