Sadly, the hype for this game far outweighed the actual experience. Most of the negative reviews I'm seeing have the same kind of complaints I did, so at least I know it wasn't just me being overly picky.
Cafe
The biggest complaint or confusion I've seen was that there was no currency. Your cafe and critters both do not earn money. Placing furniture doesn't have any kind of threshold, you can just pile it up and get as much as you want and that detracted from wanting to decorate the cafe, since you know you didn't HAVE to.
The mini-games in the cafe were repetitive, and I quickly started choosing the other option where you host a party, date, etc, and only have to choose a few items, as opposed to actually serving the customers even though I *think* you get slightly more experience serving people. They also just randomly appear in the cafe, which I think could be a slight gripe, but it has a such an unfinished feel to it. Your furniture upgraded as you rescued critters, it didn't really feel like you were earning better furniture, and I gave up checking what I'd unlocked about half way into the game. The critters that you choose to "help you" while you serve customers DO NOT help. The amount of times my partner or friends had to hear me say "ARE YOU HELPING OR HINDERING??" makes me feel bad for them. They just get in the way and give no bonuses whatsoever.
Habitat and Critters
The habitat where you can interact with your critters has a few actions you can do with your critters. You can give them treats with NO explanation how they actually work, the summoning of them feels somewhat clunky or unfinished and there's no explanation to use the bell to call them. I fortunately saw the bell when I entered, however I have seen a few people say they entirely missed it. Most of the actions available here DO NOTHING. You can interact with your critter after you unlock them, I chose to just push the play option, it somewhat unlocks them for use in your cafe. But that was also discovered through testing, not by the game explaining that. Washing, brushing and playing with your critter all essentially do absolutely nothing. Even as a child, I would be confused as to why I was doing these things. The only option I really used was the customise, which is purely for aesthetics, but the final form gave me an easy way to tell when I'd maxed out a critter's level. However all the critters have exactly the same colour as the final form, was that laziness or on purpose... who knows!
Other Locations
The areas outside the cafe containing blueprints were just lifeless and sad, I only spent as much time in those as I did to collect all the blueprints. One of the blueprints I got to "unlock" a new hat, gave me a hat I already had with the base game upon starting a new game, that was a sad moment, as the character creation is possibly the best feature in this game, closely followed by the Naruto run animation, kudos for that one. These areas also served as a way to enter the puzzle zones to unlock new critters, but nothing else happened there. Once you realise the pattern to how this game works, it's all very noticeable unfortunately.
Puzzle Areas
The puzzle areas were probably the most well designed gameplay in the entire game. They actually made you think, your new power-ups were somewhat exciting to go and try. However the difficulty of the cafe games seemed to be directed at children, while the puzzle areas would have likely stumped me at say... 10 or under. There were also parts where you had to press a switch and then zoom to another platform with such speed and precise timing, if I wasn't playing on a controller, I'd have wanted to throw my PC out a window.
Story
Typing this, I'm saddened to say, is more pointing to the lack of story. A friend gives you a whole cafe, why? It'll be fun maybe... An anonymous person sends you potions to travel to the puzzle zones to rescue critters. Why can't they rescue them themselves? Why were the critters captured in the first place? Who is doing this to the critters and creating puzzles to guard them? Who knows, not you. And you never will. The appearance of the character who has been sending you the mail at the end of the main game, meant nothing to me, it was only because I watched someone else starting the game again that I even realised there was a correlation between that story and this character. I had forgotten about the opening entirely.
Specifications
Spec-wise... Critter Cafe crashed my PC several times and made it sound like it was taking off. I can play most games on high-ultra quality, even though it was on the cheaper side, but it just did not appreciate this game for some reason. I ended up turning the graphics down to Low to finish off my achievements just to try and avoid any more crashes. I also tried this game on a lower setting on my laptop, it made my laptop so hot it almost burnt me to touch the corner the processing unit is in, this is with a cooling pad too. I do not understand how a game with these graphics can be quite so intensive.
Conclusion
While I'm saddened to have to give this game such a, perhaps harsh, review. I was honestly disappointed and felt I'd wasted my money. 1 hour of gameplay should not cost someone over $2. I shouldn't feel like I'd wasted my time after finishing a game. While I understand I am an adult, I thought a lot of times during this that "wow, I'd have loved this if I was a kid." and felt I was missing out. Some of this thought process was also due to the fact that I definitely wouldn't put as much thought into the flaws of a game, but also that I probably wouldn't even notice them. I'm sorry devs, truly. You have a great foundation here, but I can't help but feel there's just no soul, or perhaps a lack of funding going on here.