H2 Interactive will release Raiden IV: Overkill on Steam. Unfortunately Ikaruga did not make it to GoG yet but H2I released Raiden III on GoG already. So I think there are chances we will see this game here.

Please vote for it: http://www.gog.com/wishlist/games/raiden_iv_overkill

Voted, Raiden IV is the better of the modern Raiden games. III is cool, but IV brought it back to the awesome that was the first two.

It is available now on Steam and apparently a good port. We really need this here too.

Voted. I wish we could get Raiden 2 as well.

Voted of course!Keep those SHMUPS coming(wondering if we'll ever get ikaruga)
Talking about it,if you are interested http://www.gog.com/wishlist/games/ikaruga

There are already so many great shmups on Steam.

Kalypso is releasing there newest titles on GoG but they havent brought Sine More over to GoG yet.

Degica will be releasing Eschatos, Deltazeal and a few Cave shmups soon on Steam. They also released a few games, including Crimzon Clover, here on GoG. But I heard that GoG does not really want that kind of games.

please gog.com. Raiden IV Overkill in gog edition

It finally got released here :)