A squid girl shows up to invade Earth in retaliation for the environmental damage done to the ocean by humans. Unfortunately for her this is comedy so instead of squid loli domination, her invasion attempts only end in funny failures. There isn't much else to the story, aside from the unique main characte this is a by the numbers slice of life comedy.
As expected of a 2010 anime, Shinryaku's animation is very bright and colourful but like the plot its just decent but nothing special.
OP and ED were mediocre while the background music fit the scene without being too noticeable (as it should). Voice acting was solid with Ika being easily the standout with her determined attitude and distinctive speech pattern degeso~.
Most of Shinryaku's characters can be summed up in three words or less. Eiko, easily angered. Chizuru, yandere. Nagisa normal and scared. Sanae, stalker. Ayumi, shy. Their purpose is really to just to play off the main character Ika and create funny situations. Fortunately the best part of Shinryaku Ika Musume is Ika herself, who's antics make the show quite enjoyable to watch whether it's her “invading” the local school, struggling through shrimp withdrawal or discovering the power of umbrellas.
Shinryaku Ika Musume is a entertaining slice of comedy with a great main character that is well worth your time if your in the mood for something lighthearted and fun.