Is this guideline official? Are you one of the organizers? I would like to know some of the organizers thoughts on this matter, especially because I've seen in multiple places now that the "keep it as GB as you can" isn't really enforced. Also if you go all out on the specifics why nothing about audio/sound?
Consider it this way: Probably nobody will appear at your door and kick you in the stomach if you break any rule, even the resolution one. :)
Stick to the given resolution, four colors, and use tiles and sprites rather than anything polygonal/dynamic and you're fine in most people's opinion.
If your game plays well and feels like it could have been on the Game Boy it's fine, even it would have been slow as hell.
If you want, look up "Elite" for the Nintendo Entertainment System. Yes, it's been done and it's in full wireframe 3D even though the NES had no 3D hardware (or software) support and essentially tiles and sprites only.
For most it's just for fun, a learning experience, or some creative way to try something new and share it with others.
If you want to participate, just do it. Don't worry too much about the rules or restrictions. Bend them as you see fit, just try to stick close to them.
Also keep in mind the notes above are mixing up GB/GBC a bit. Originally you only had your 4/3+1 grayscale palette and nothing more. The palette swaps for sprites were introduced with the GBC for obvious reasons.
Phu! I mean, for us n00bs that are just starting out with game dev. that would have probably been... impossible? :D Well, not necessarily, but definitely harder for sure. So I for one like those bendy rules a lot more, I don't think the goal here should be creating an emulator for this thing :)
Nope, there are two palettes for sprites which source from the 4-shade gamut. IIRC GBC uses 8 palettes for the sprites and those are sourced from that 5:5:5 RGB cube with the really weird gamma ramp and side effects.
They're not official guidelines. The guidelines on the main page are the only guidelines. They're neat meta objectives though.
The main page has rules. My post has optional guidelines. They're not official.
As for sound, easy solution is to just make something in Deflemask.
Here's what it uses anyway:
- 2x pulse wave (12.5%, 25%, 50%, 75% duty cycles)
- 1x 32-sample 4-bit wav channel with very limited volume control (best to assume this just does on/off)
- 1x 15-bit/7-bit (selectable) LFSR noise channel, frequencies are kinda weird, if you don't do any freq sweeps you should be fine
Each channel supports hard-panned stereo (left/centre/right).
Volume goes from 0 to 15 inclusive. Not sure what the actual lower/upper bounds are on the period. It appears to be a simple voltage sum, unlike some chips which use logarithmic volumes.
For the curious, at least one pulse channel has a freq sweep unit, and I think both have a volume envelope unit each. You do not actually need to know about these as you can replicate their behaviours manually.