The curvature of wave propagation method (CWPM) models gravity in flat three-dimensional Euclidean space, capturing both weak- and strong-field regimes. Gravitational effects arise solely from the spatial gradient of the speed of light, wave—particle duality, and the resulting curvature of wave propagation, which together yield an explicit, closed-form, velocity-dependent acceleration vector that is analytically more compact and natively simpler to implement than the complex Parameterized Post-Newtonian (PPN) expansion series. CWPM N-body simulations reproduce the classical solar-system tests of general relativity—including Mercury’s perihelion advance, light deflection, and Shapiro delay—while executing up to five times faster than PPN integrations. A 15-body simulation confirms Mercury’s precession and demonstrates convergence under time-step refinement. Independent implementation and testing by Kuijpers (2025) in his pre-existing Solar System Simulator confirms CWPM matches GR-based PPN DE405-referenced deviations to within <30 km RMS over 600 years, while running ~5× faster. Although CWPM places the photon orbital radius at the Schwarzschild radius Rs = 2GM/c² (rather than 1.5 Rs in GR), it predicts a black-hole shadow diameter of 2eRs, only ~4.6% larger than the GR value—well within Event Horizon Telescope uncertainties for both M87* and Sgr A*. Included MATLAB scripts enable students and researchers to compute solar-system orbits, light propagation, black-hole shadows, star-cluster dynamics, and deep-space trajectories using a unified framework based on a single explicit equation of motion, offering an accessible, computationally efficient learning tool for physics education and independent research.