Why did I buy this? What did I actually get?
I seemingly can't get enough of monster supplements. Additionally, bugs freak me out. Couldn't resist.
Have I used this, or will I use this?
I've not put any of these bugs into the campaign I currently GM, but as long as this little PDF doesn't get lost on my HD, I see getting some mileage out of this. If I put in a little work to up their CR, I could see giant barnacles getting some use in the very near future.
How is the fluff?
Good. The fluff describes the creature well, and scales them up to size to work in their environment.
How are the mechanics?
Well rounded, and a cursory glance at the math seems to check out, but one or two of these creatures have mechanics that are too simple for my taste. The Giant Carnivorous Butterfly complements the Giant Carnivorous Caterpillar, but has nothing unique of its own. In addition, the Giant Water Scorpion has a unique Hold Breath ability, but outside of trying to drown it for two hours, would likely see no use in combat. The barnacles have an Immobile ability that make it immune to forced movement, but not teleportation; while this is cool, logic should dictate that a barnacle so teleported would no longer be anchored to its location, and would lose the Immobile quality.
Other creatures do better, whether it's as simple a Giant Stinkbug's stench, or as cool as the Gargantuan-sized Giant Mantis Shrimp's Ambush Predator ability to effectively employ stealth.
The Immune line of the statblock reads mind-affecting effects as often as it does mine-affecting; not too big of a problem in this case. More concerning is that page 6 splits the two creatures listed by a horizontal rule, while every other page has done so by column; in doing this, the Giant Stink Bug's statblock moves to the next column between Ability Scores and BAB. It's a jarring shift, and made it hard enough to read that I spent a minute or so wondering if the designer had forgotten the 'Stink' part of the Stink Bug altogether. Finally, the Giant Water Scorpion has it's Charisma listed as "?".
Outside of these issues, the layout and fonts used are readable.
Was the price fair?
$3.95 is a bit steep for this PDF as is. If the aforementioned editing errors were cleaned up, and the less-exciting creatures beefed up or replaced, then I think we'd be in the ballpark, but I personally wouldn't see myself selling it for more than $3, considering the illustrations, I believe, are public domain at this point. If the author DID have to license the artwork, I would retract that previous comment - feel free to correct me if you'd like. To their credit, Octopus Apocalypse does a Free Monster of the Month release, including the Giant Whip Spider presented in this book.
Earwigs live up to the terrifying horrors they are in the real world.
Least favorite part?
While I enjoy the authentic Victorian illustrations, I do practically all of my GMing on VTT. The art style is clearly listed in the description, and won't affect my rating, but I nonetheless always enjoy having full-color illustrations devoid of excessive background for easy token generation.
3/5 - Not terrible, but nothing to write home about either. This rating represents how the average consumer should come away from my review; if you are like me, and can't get enough of weird bugs, consider the rating a 4/5 instead.