Digital integrated circuits continue to grow in scale and complexity, and functional correctness depends on understanding how real hardware behaves under a wide range of physical effects. This course presents a practical path into the engineering challenges that shape modern digital design. It moves beyond basic descriptions of logic behavior and focuses on the hidden factors that often disrupt an otherwise correct design. These factors include power-related behavior, metastability, unreachable code, clock and reset domain interactions, X-propagation, and the influence of real-world constraints on register-transfer-level structures. By studying these concepts in depth, learners gain the ability to reason about digital systems in a way that matches real silicon rather than idealized diagrams. The course organizes its material around fundamental design challenges that appear in nearly every integrated circuit project. It begins by examining scale, automation, power, and physical constraints that influence how designers write and structure logic. It then explores how unreachable code can hide design intent, reduce verification quality, and distort coverage metrics, and how formal ana...