Ciocarlan et al (Ciocarlan, 2018), developed a wellbeing game that utlised some of Cialdini's well-known principles of influence and persuasion (Cialdini 1984) to persuade players to perform real-world acts of kindness. The artefact was used to address a number of research questions including the impact on subjective wellbeing. Although this was a significant piece of ongoing research, the artefact they used would make an interesting muse for a Minecraft mod. Although Ciocarlan et al's results were inconclusive, the results could be used as a steer to scope-down to something achievable in the timescale for a Computing project.
This would be a DBT project, so research on the effectiveness of the artefact in behaviour change would NOT be required.
Experience of Minecraft modding, as well as keen interests in Persuasion Psychology and Positive Psychology would be needed to do something worthwhile in the timescale available to you. Are you persuaded?