The review is for the whole series since it's not an episodic storytelling but rather one big story. Nevertheless, here are my separate rating for the first 4 books:
1. ⭐⭐⭐⭐
2. ⭐⭐⭐
3. ⭐⭐
4. ⭐⭐
More details:
GOOD
In general, the story is interesting and makes you keep reading. The main character is likable and the rest of the team is colorful and engaging. Additionally, sidekicks—a talking dog, cat, and jinni—are fun. At least in the beginning. Hence, the highest rating of the first book. It keeps you reading despite further listed negatives.
BAD
Jokes, snarks, and whining of the talking animals and jinni become stale pretty fast. They are fun in the first book, then tolerable in the second, but they just blatantly annoy in the third and make you want to completely stop reading in the fourth book. And they never change. It's constant recycling of annoying pets' talks about food and desire to eat. Again, and again. It's just too much and becomes extremely annoying and not funny anymore.
The story develops too slowly. Craig Alanson, apparently, is more interested in writing about talking animals and recycling their food demands than developing the story. It looks like the author is fighting procrastination: he throws in anything possible—mostly in the form of stale recycled food jokes, bickering, snark comments, and useless conversations—just not to move the story further. A 20-minute episode of the Rick and Morty show has more story than all 4 books in this series.
As a result, if we cut out most of the annoying interruptions by useless bickering about food that doesn't move a needle, the four books could be neatly packed into one proper book.
I'm not sure I'll read the next book. I already can't stand these animals with their constant whining about food.