Guided by the Next Generation Science Standards and elements of problem-based learning, four human-environment systems simulations are described in brief--carbon, energy, water, and watershed--and a fifth simulation on nitrogen is described in more depth. These science, technology, engineering, and math (STEM) education simulations illustrate design principles that make them engaging to students, such as dynamic visual environments that are controlled by the user and immediate visual feedback to user actions taken. The simulations are contextualized in real-world natural resources management challenges involving biogeochemical cycles, such as Gulf of Mexico hypoxia, which provide an opportunity to "win the game," while the introduction of complexity in steps provides scaffolding. Pretest versus posttest results indicate a substantial and statistically significant improvement in learning outcomes resulting from using the nitrogen simulation, though there was no comparable pedagogical control group. Attitudinal feedback indicates rich student engagement with the nitrogen simulation.