A new preview of SIREN: Blood Curse over on ThreeSpeech, they tell us that each episode will weigh in at around 600MB. For those hoping we get it all on disc like Japan will be getting, there is no mention of it in the article.
With a total of twelve episodes, that’s around 7.2GB that will be taken up on your HDD. You can always delete an episode and download it once more though. Hopefully although, North America and Europe will get a Blu-Ray release as well.