It's a slice of life story
The anime is a slice of life, so if you're expecting a strong story, then you'll want to avoid Squid Girl. Although there are a few story lines which hold through both seasons of Squid Girl, they're not really anything too in-depth, and the story comes more from character interaction more than anything else.
The artwork is uniquely generic
There wasn't anything stand-out about the artwork, nothing that made me think they went the extra mile with it. However, everything from Squid Girl's design to the attention to detail with the cafe's interior, and the unfixed hole, shows that although they didn't push the boat out with the artwork, they definitely paid close attention to everything they did, and made sure nothing was there for no reason.; for example the squid tentacle loading screen style transition (see the main image as an example).
The characters have character
Squid Girl is the first anime I have seen to portray a sibling rivalry as I have experienced it. It's not always punching, or throwing each other's stuff, or competing, sometimes it is "I will never speak to you again, and if something happens to you, I don't care as it's your fault". Although Eiko and Squid Girl aren't related, they become like sisters, and having this type of sibling rivalry really adds to the connection they share.
Along with this, there's how Eiko, Squid, and Takeru see Chizuru. Chizuru is portrayed as a nice big sister, until you get on her bad side, then she'll kill you. This is a great portrayal of siblings too, as there are siblings who have that great relationship with their older siblings, but know that if they do X then they had better be prepared for the consequences.
Outside of the sibling relationships, we have Sanae. I feel like she was added for comic relief, but plays a big role in Squid's relationship to the other characters, as Sanae inadvertently makes Squid get closer to Eiko, and find security in her. She also has a closeness with Cyndi, which further alienates both Sanae and Cyndi, plus the other Scientists, from Squid.
Then there's Squid herself. Although she's an invader, she never wants to cause harm, she would be the worst choice for an invader. But even so, she tries her best to achieve this goal, and the characters around her don't try to stop her, they just let her fail, and are there for her when she needs them.
All in all, Squid Girl is a funny 2 season anime, which is definitely worth a watch for the comic relief alone.
Comic relief is really what I needed these past two weeks, as I was made redundant from my job and needed something the cheer me up. Squid Girl was one of the anime that helped cheer me up, Little Witch Academia and Tamako Market were the other two. Reviews for them will be coming soon, I'm hoping the next review will be the last one before I get a new site design live, as I have slowly been redesigning the entire site. So hopefully reviews will start to have more to them; embeded videos for funny scenes/music/etc. from the anime, more images, and generally a nicer layout. All of that is to come though, so until then じゃね!