Singapore's strong performance in international benchmarking studies--Trends in International Mathematics and Science Study (TIMSS) and Programme for International Student Assessment (PISA)--poses a conundrum to researchers who view Singapore's pedagogy as characterized by the teaching of facts and procedures, and lacking in constructivist learning principles. In this paper, we examine the impact of different curriculum innovations on critical thinking as measured by the Watson-Glaser Critical Thinking Assessment-UK (WGCTA-UK). This includes two innovations that are subject-specific and short-term, one that strongly infuses the arts into the curriculum throughout the whole course of study, and the innovation of the Integrated Programme (IP) which allows academically stronger students to skip the GCE "O" Levels and enter directly into the next level of education, with the time previously allocated to exam preparation now spent on greater breadth in the academic and non-academic curriculum. This paper takes the sociocultural approach to investigate the contexts, process, and outcomes, reports the state of critical thinking, and sheds light on how critical thinking is being promoted. Through our analysis, we find support for the claim that only curriculum that is rigorously designed to foster critical thinking competencies will reap the intended student outcome.