Kangoku Senkan

Both series have beautiful women and lots of rape. 

Both hentai tells story about a secret agent who is assigned to oversee an suspicious organization/group but end up as slave rape victims 

They have very similar art style and are made from the same company. 

They have very similar art style. 

A series of experiments being done to the girls resulting in bold results. 'Kangoku: Injoku no Jikkentou' does not have any mind controlling involved but seeing blackmailing girls to do as you command is pretty tempting especially if their friends are being put on the line should any disobedience arise. The changes on the girls are not in the tentacles stage which makes it easier to watch. 'Kangoku Senkan' is more on mind controlling experiments that haven't been tested and confirmed to work, the unknown results would be satisfying to watchers and the vengeance of the antagonist to those girls serves as an even sweeter revenge due to their past encounter which people might enjoy. read more 

Mind controlling in both series resulting in...well anything. Women are being ordered against their will to perform acts that are out of their control. In terms of mentality, 'Kangoku Senkan' is shown to have tougher characters that will not bend easily even though they already did in another personality. 'Oku-sama wa Michael' focus on a more fragile woman and in a way, that would satisfy watchers either based on fav genre or the fact that the woman cannot defend herself. 

The uniforms for both the males and females (plus the logo of their forces) all are similar to one another. The warships remind me of Minerva as well.