> It would have been nice if they had tried a quantitative comparison with the Risc-V RV32I
It would. If they had a Time Machine. ZPU is over a decade and a half old… Back from from when we called RISC-V just "MIPS"
But since you asked. It IS small. The smallest sane RV32 core I can find is PicoRV, which uses 750-2000 LUS[1]. SERV [2] does claim to only need 440 LUTs, but its performance (most instrs take over 32 cycles) makes even ZPU seem speedy... The ZPU uses 442 LUTs[3].
[1] https://github.com/YosysHQ/picorv32