There aren't any threads around except this one that discuss and share potential game mechanics, bullet patterns, and the like. A place to get inspired if you can't think up of anything.
GAME MECHANIC #7: Tengu cameras as bombs
charge bombs
You know how the Perfect Freezes work in GFW? It's something like it, but moreso towards StB and DS's camera functions.
Two characters, Aya and Hatate.
Their bombs are replaced by a camera photo. Their bomb charges up similar to StB and DS, with bullet cancels and all, but the charge received from cancelling bullets has an exponential curve downwards based on difficulty, so that things don't get too OP. e.g. Taking a picture of a nuke sun gives 10% charge on Normal, 15% on Easy, 5% on Hard, and 1% on Lunatic, for example. To take this further, the charge received would have to go into decimals, like 0.1% on Extra, 0.01% on Phantasm, etc.
Aya has the effects shown above, along with high zoom, long exposure time, large area, but a very slow charge (~1% every second when normally focused, 5% when charging).
Hatate has a 1.5 times charge multiplier to the above (i.e. 15% for a nuke on Normal). Very fast charge (2x Aya), very low zoom, short exposure time, and a smaller/thinner area covered.
Aya could be used for getting rid of bullets from the source, like homing bullets.
Hatate could be used for removing bullets that are right next to her.
And so on, and so on