Virtual reality and gamified mechatronic systems can increase patient engagement in locomotion exercises, but their high cost and closed architectures limit clinical adoption. The present study reports the design and implementation of a customized cost-effective treadmill-based platform that integrates a Unity3D environment with Arduino-driven motor control. The system delivers real-time visual feedback through user-selectable avatars traversing a forest trail synchronized to fully customizable speed profiles. Clinicians can easily create, modify, and sequence multiple exercise protocols via a graphical interface, while the platform records and logs physiological (heart rate, RR interval) and performance (speed, distance) data continuously for subsequent analysis. Low-cost treadmill was mechanically adapted to accept external speed commands, a Polar H10 chest-strap was integrated via an Android application, and reliable serial communication between Unity3D and Arduino Uno was established. A dual-display configuration enables therapists to monitor live biometrics and trigger emergency stops, while users experience immersive feedback on a separate screen. Preliminary system testing demonstrates reliable real-time control, accurate data acquisition, and continuous user interaction. This unified Unity3D-Arduino ecosystem offers a flexible, low-cost solution suitable for clinical rehabilitation and research data collection.