Unfortunately, there's no industry standard for how gate counts are defined. The Altera FPGA devices that I'm familiar with use "Advanced Logic Modules" (ALMs) which are a combination of look-up tables (LUTs), registers, and other advanced features that are combined to create the discrete logic behavior. Xillinx calls their ALMs by a different name, and they are not guaranteed to have the same features or capacity. Even different device series from the same manufacturer may define their basic logic building block differently and have different capacities.
I have implemented the hack computer system in a Cyclone V FPGA device and it utilized 384 ALMs (2% capacity), 56 pins (25% capacity), and 1,048,576 memory bits (33% capacity) for ROM, RAM, CPU, VGA controller, PS2 controller, basic debugger circuitry and I/O.