Quantum simulations of Hubbard models with ultracold atoms rely on the exceptional control of coherent motion provided by optical lattices. Here we demonstrate enhanced tunability using an optical superlattice in a fermionic quantum gas microscope. With our phase-stable bichromatic design, we achieve a precise control of tunneling and tilt throughout the lattice, as evidenced by long-lived coherent double-well oscillations and next-nearest-neighbor quantum walks in a staggered configuration. We furthermore present correlated quantum walks of two particles initiated through a resonant pair-breaking mechanism. Finally, we engineer tunable spin couplings through local offsets and create a spin ladder with ferromagnetic and antiferromagnetic couplings along the rungs and legs, respectively. Our work underscores the high potential of optical superlattices for engineering, simulating, and detecting strongly correlated many-body quantum states.