What would you say is Cave's definitive arcade shmup title?

[elvis]

But if "definitive" means "the best", then... go look at the Top 25 votes for answers.

"Definitive" most certainly does not mean "best".

DDP to me defines Cave's shmup style. There may have been games since that were better, but you take one look at a Cave shooter and you know it's Cave for certain style (both visual and game engine) reasons - most of which were defined (hence the term "definitive") in DDP.

Yes, Batsugun and DonPachi came before it, but both were baby steps into that style. DDP was the defining moment of Cave. Everything pre was a beta test, and everything post has been a tweak. Love it or loathe it, DDP defined that style.

[roker]

Ketsui

Cave

refined

[shoe-sama]

why is it that all cave games give you a zillion bombs and have a more powerful shot for holding down shot button?

[Arvandor]

why is it that all cave games give you a zillion bombs

To make it easier on noobs. It's also why they heavily penalize your score for bomb use. To balance out the ludicrous number of bombs you get.

and have a more powerful shot for holding down shot button?

Because giant lasers are badass.

[ForceDevice]

Everything pre was a beta test, and everything post has been a tweak.

Genre definitions aside, I just imagined that would be a cool sig text.

"Everything pre-ForceDevice was a beta test, and everything post has been... erm... not as good".