Very close, both of them have aliens and a lot of ecchi moments with a bit of action.
Both anime are echhi/harem with the basic premise of normal high school male living (by chance) with beutifull alien female. With a lot of gadzets.
They're both harem series with multiple types of girls liking the protagonist, who is very unaware of the situaion. Besides that, both of the main character girls are from space, big chested, wear tight space suits and have small helper(s). Both series have ALOT of fanservice as well as a somewhat similar art and story.
Both animes have a female alien coming from out of outer space witch stays with the main protagonist. They also both have amazing technology.
Sample Plot Same Genre Same Alien female main Character
they got 90% same like alien that comes from some were
the alien girl always sleeping on the male protagonist bedroom while naked
plenty of girls (harem)
same they love the male protagonist
same Plot ,
also same Alien Female main Character Boobsy , Tall , Foreign Like , No shamless while naked or doing ecchi things
A cute, flirty alien girl with a tail meets the male protagonist, with a tendency to whip out random alien gadgets. The main protagonist has a harem. If you like one, you'll like the other. Ecchi-comedy.
Its very very very similar , both have alien dropping by on the Earth and Staying in a Boys house , even sleeps together xD . they have same atmosphere and the main girl characters have tails xD .
Sudden alien / girlfriend appearance. Multiple girls that like the same guy, some of which are childhood friends.
It's like watching the same anime twice, a beautiful alien appears in both, and of course, falls in love with the main character, but maybe "To Love-Ru" is a bit more childish than "Asobi ni Iku yo", but both are pure awesome, if you liked "To Love-Ru", you will definitely like this as well.
Alien girl just randomly pops out in MCs life followed by more alien and normal girls. Both are harem ecchi comedy. Both main heroines lacks common sense a bit.