According to a post by the game’s producer Kenichiro Takaki on Twitter, the full game (including all characters, which come in two different packs called “A” and “B”) will be 3-4GB in size.
Dekamori Senran Kagura will come in two different packs; “Pack A” will include thirteen different characters to choose from, while “Pack B” will include another eleven – a cost of 2,315 yen (~$22.20) for each. You’ll also be able to download a “Mega Pack” of sorts, which will include both character packs and the full game – and this will be the product that reaches that 3-4GB range. We’ve got no information on the price of the “Mega Pack” though we hope it’ll be reasonable.
The game releases March 20th in Japan.