This study examines the dynamic response of a selected wave energy converter (WEC) in long-crested waves ranging from linear to steep scenarios. First, an overview on the state-of-the-art for WECs is documented, also highlighting the fundamental role of renewable energy and carbon emission reduction in addressing environmental challenges. Various WECs technologies are discussed comparatively and, the innovative device, C4 CorPower WEC, proposed by CorPower is selected for an in-depth analysis. This is based on a point absorber solution, already at a high Technology Readiness Level (TRL). The theoretical framework for the dynamic analysis is based primarily on linear potential-flow theory, but weakly-nonlinear hydrodynamic effects are also examined; moreover, viscous-flow effects are included through empirical formulas.