I just added Taito's Crazy Balloon to the repository
I wanted something smaller (and simpler) to do as near as damn it from scratch to get used to the framework and FPGA land in general.
simple core, z80, character graphics, 1 sprite and some analogue sounds (SN74677 done as samples since the board does things to the chip not mentioned in TI's documentation, so sampled from my cab instead)
Crazy Balloon
Re: Crazy Balloon
It is only because I needed to remind myself what the code was meant to do 
it does vary from the real schematic in a couple of places, for instance, it doesn't use wait states on video ram but uses dual port ram instead, however the game speed is controlled by the interrupt so it will not affect the game play at all.
plus I didn't manage to not use samples (only for SN74677 effects, and I may fix that later once I get the PCB on the test bench to see exactly what some of the odd things it does to the sound chip achieve, since they are not mentioned in the data sheet) - I did get the explosion working correctly, but could not get the other two sounding anything like the real cab!
it does vary from the real schematic in a couple of places, for instance, it doesn't use wait states on video ram but uses dual port ram instead, however the game speed is controlled by the interrupt so it will not affect the game play at all.
plus I didn't manage to not use samples (only for SN74677 effects, and I may fix that later once I get the PCB on the test bench to see exactly what some of the odd things it does to the sound chip achieve, since they are not mentioned in the data sheet) - I did get the explosion working correctly, but could not get the other two sounding anything like the real cab!