the Amazon JP listings for Darius Cozmic Revelations are up but they don't currently have the Prime Day bonus listed (a digital PS4 or Switch copy of Darius EXTRA MD, a revised version of the port featured on Genesis/Mega Drive Mini) so maybe wait until they straighten that out

Darius EXTRA MD for PS4/Switch is one of those "buy within the next 48 hours or never get legit access to this thing ever again" promo deals, but it is getting a MD cartridge release as well so it'll be out there one way or another

aight, Darius Cozmic Revelation Amazon Prime Day promo versions are up, get em before 13:59 Oct.14 time if you want the Darius EXTRA MD DL code

PS4 https://www.amazon.co.jp/dp/B08KWGQNX1/ 
Switch https://www.amazon.co.jp/dp/B08KWGBWTL/ 

the LE/DX links keep going up&down, check for yourself if you so desire

for a basic rundown of what's in the LE/DX packs, check this thread https://twitter.com/gosokkyu/status/1314528732787343360

tldr: the LE's basically identical to the one being sold internationally & the DX include Darius EXTRA MD on a functional cart, but it'll be sold separately later & isn't bundle-exclusive