Participatory interfaces in (semi-) public spaces represent a promising area within Human-Computer Interaction, enabling users to engage with interactive systems that are openly accessible and support decision-making. While participation is well established in application and system design, its translation to public interfaces introduces new opportunities and challenges. This paper presents a systematic literature review of 30 publications identifed through PRISMA guidelines, focusing on interfaces, frameworks, and toolk-its that enable user participation in (semi-) public spaces. Using a dual-axis lens, based on stages of participation and degree of involvement, we introduce the Involvement-Participation Matrix to analyze how participation is framed. The matrix reveals a diverse landscape of approaches while also identifying opportunities for deeper user agency. Our findings offer a foundation for future research to develop clearer typologies, critically examine assumptions about public users, and explore how the placement of participatory interfaces might contribute to more inclusive and diverse digital interactions.