This game is cute. I really enjoy cozy games, particularly when they let me play with cats. The cats meows were adorable and made me happy each time I heard one. I liked that the cats had different personalities and behaviors. The animations were cute; I particularly enjoyed watching them run and do what looked like a little jump.
A few things that stood out to me that I think could be improved.
The text is hard to read. The font itself isn't terrible, but the contrast and size makes some of it difficult to read. I feel like a darker text, instead of the white with an outline, would help make it easier to read. On a similar note, having a fullscreen option would be really nice. It would help make the text easier to read, and cats and humans easier to click on.
The cafe didn't take up the full viewport when my browser was at 100% zoom. There were grey bars at the side and bottom. The money was shown in the grey space at the right side and the cat names/level, adopt, upgrade, and cafes were in the bottom space. Adjusting my zoom adjusted how much of the viewport the cafe took up. I found playing the game at 70% zoom, which left a small grey bar on the side and the bottom grey mostly covered by the bottom panel, looked the best from a visual standpoint.
I think it would be nice if it was clearer which cat I had selected on the adoption page. Having something like a border around the selected cat would have helped.
I think it also would have been nice if there was a way you could look at info on the cats again after you had adopted them. You can see their level and name by mousing over them, but I think it would have been cool to be able to click on their name or something and see their personality and More Info, and maybe learn a little bit more about them as they level up.
The cat named Silver is called Velvet in the More Info about them. Their name is Silver when you mouse over them after you have adopted them.
The text about the customers went by faster than I could read it. It was pretty easy to figure out what I needed to do without reading it fully, but it would have been nice if it hadn't been so fast.
I had a customer at the counter, and another customer came over and looked like they were trying to push the first one out of the way. I then had two customers approach the counter at about the same time, and they got stuck pushing each other in different directions. The third customer came over and joined the pushing contest, as did the fourth when they arrived. The first time I played, they all just stayed stuck for the rest of the time I played. I played a second time, and tried timing when I would click on the customers at the counter to see if I could keep them from getting stuck on each other. I was actually having a fair bit of fun trying to keep them from getting stuck, and even when they did all get stuck together, they were able to keep inching around until one was facing the right direction to register and be clicked on.
The cafe level progression didn't fully make sense to me. Sometimes it felt like I was on one level for a while, and then I would jump several levels in a short time. Once the fourth customer arrived, the level didn't seem to be as important. Edit: As I was writing this, one of my teens committed that they thought the cafe level was based on the number of cats and their comfort levels. Doing a little bit of testing, I think they are right, but I'm not 100% sure. I think it would be good if you made the cafe level a little clearer.
I'm looking forward to seeing what all you're planning on adding to this. Upgrades and new cafe sound like fun. And of course petting all the cats!