Hey, I remember getting your game on Android and even paying for the ad removal. I can't find it anymore on the play store and the APKs I download do not recognize my license.
Please help?
It's specifically the rant that caused me to be confused and worried.
Because while you allow dithering, the rant made it sound like flickering as a whole was completely banned if it made it look like the palette had more colors than were ever displayed, even if there was no palette swapping or "true" 5th color involved.
Hence why I included visual examples explaining how flickering tricks the eye into seeing more colors than there are. I just wanted to clear up confusion.
Thankfully your co-host clarified that sprite flickering was completely off the table, so now I won't waste time making a game that would auto fail the jam's rules.
I'd argue that the game boy LCD's response time would actually help to sell the effect better. The flickering would look even bore like an in-between color thanks to that screen's ghosting.
In fact, here's an example of it being used in castlevania II. Real gameboy hardware.
When belmont goes ino the water, or in fact, when any item goes into the water, they start flickeing in a manner not too dissimilar to what I did.
The only difference being that i flicker alternating lines instead of the whole part of the sprite that is submerged.
Part of why I love the game boy is how the devs essentially "cheated" the limitations by essentially turning them against each other.
Intentionally using ghosting as a pseudo teansparency effect or for motion blur, or layering sprites to get more details, all those small tricks that make you wonder how they did it.
If you want, I can try to collect more footage of examples.
Let's assume that I am making a game with the jam's restrictions in mind. I decide to use flickering effects. There is no palette swapping. Does it still count as a 5th color?
Visualisation displayed below.
As you can see in the gif, the portrait of the robot gets covered by a set of oscillating lines. They move up and down every frame, to the point that it creates an optical illusion of a 5th (well, in this case 4th) color, specifically for the purpose of simulating translucency.
50 fps gif

However, as demonstrated by the photo below (or by looking at the gif's individual frames), there is absolutely no additional color beyond the black, white and red displayed.
static screenshot

This flickering is something you could do on the game boy's display.
But your explanation of the color palette rules make me worried that I'd be disqualified for using this technique, despite respecting the hardware's limitations.
So, would a game using flickering for the optical illusion of transparency be disqualified?
Uhh... Just a heads up, you should probably change the commercial license from CC0.
Currently, anyone (wether they purchased the license or not) can redistribute, use without attribution, or even resell the tilemap without any consequence.
But then again... Since it's already being distributed as CC0, the genie's out of the bottle and your work is now in the public domain.
On another note, this is a really good tileset! I'm currently using it in the development of a game, and It's working really well for me!
To answer your question, here's the template I created a few months ago
It's properly commented, and I can send you a free copy if you want
The game feels nice to play, and I enjoy the power-up progression. However, a big issue is that the enemy projectiles, being dark as they are, kind of blend in with the background, making the game difficult to read.
I do enjoy the artstyle and the slightly calmer pace that you decided to pick.
Pretty good overall!
Hey, thanks for the feedback! The hit flash is something that the next build will have, but about the ship UI... isn't it see-through when projectiles and enemies go through it?
Objects should be entirely visible (although filtered into a different color when going through the health bar (...wait, is it even a bar?)
Could you send me some screenshots or footage on your end? It'd be a real help, especially since recently, there has been some graphical bugs with firefox specifically.