> yeah...fantastic work! Congrats... > > What I'd like to see is an overview, a description about what was encryted in which > way...what operations are known...which are still unknown.....like Andrea's CPSII/III > blogs.... that would be awesome...
Seibu decided to make the predecessor to bullet hell shmups but their pitiful V30 CPU couldn't handle it, so they made a chip to do all the trig calculations and hitbox detection and sprite list DMA. It also obfuscates the rest of the hardware registers for fun. (Contrast with the rest of the game manufacturing world, who simply dropped in fast 68000s or in the case of Gradius III 2 of them).
As I understand it the missing bullet sprites we had for the last year or so was essentially a typo in the previous attempts to fix the game rather than a protection function that had eluded people. It often helps to get away from code you're stuck on and come back having forgotten your assumptions.
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