Snake with a USB keyboard is a ready-made Basys 3 FPGA game written in Verilog. It uses PS/2 keyboard on the USB port. Play it free right in your browser - nothing to install, no FPGA board needed.
How to play
Press F2 once so your keyboard goes to the FPGA, then arrow keys (or W A S D) steer and Space restarts. Length on the 7-segment display.
What it uses
Verilog · PS/2 keyboard on the USB port
The code: download the Verilog project (.zip) — read it, change it, and run your version with the free PC program.