So, I read this on my phone, which was small. Still, the art was good enough and clear enough that I really got into the story and really enjoyed it.
I want to say the world building is queen here, because it's fabulously done. You definitely get a sense that there's an entire world beyond what we're seeing at Beetle's house and the mall. Beetle has favorite shows, engages in fanfiction, and even has social media accounts, all of which flavor the plot and deepen the character herself (and her friends). Which leads to the next point: the characters are also queen here, because they are relatable, realistic, and great. All three main characters (Beetle, on whom the story is focused, her current best friend, Blob Ghost, and Beetle's former best friend and crush, Kat, which is not a spoiler because it's evident pretty quickly) are well-fleshed out (no pun intended) people with flaws, interests, and backstories that we get glimpses into every so often. They are easy to relate to and easy to understand, without being fluffy or 2-dimensional - the author is just that good at conveying who they are. This is particularly fascinating for Blob Ghost, who doesn't actually use words to communicate except for a short note at the very end of the book, but one still gets a great sense of who they are pretty quickly (and they are adorable). Even the "filler" or "background" characters were cool (especial shout-out to the custodian, Hester, she was lovely), and I really like Beetle's grandmother.
Character design is also A+. I love the variety of creatures in Beetle's world, just walking around like everything is normal because for them it is. There's a little kid in the mall at the very beginning who is hilarious. It's a great facet to the story.
The plot was great. It wasn't world-shaking in the sense that it had never been done, but it was quick, dramatic, flavored by excellent characters and equally excellent world building, and kept me engaged the whole time. I wanted to know what happened next to the characters, and would love to read a sequel. I think for a read-alike I would reach for Lumberjanes or maybe Cleopatra in Space.
Basically, if you've got a kid in your life, particularly one who likes Halloween-flavored things, friend stories with adventure, or just excellent graphic novels, this is a great choice.