After reading your reply I opened the game in a Private Window to try it fresh, as I did not see a reset/start new game option, and didn't feel like clearing the files manually. You may want to add a new game or reset somewhere for testing like this.
Looking for it, I did see the symbol and was able to befriend the first being. I think the issue is that there is a lot going on with the being's art, and everything overhead. The icon blends in with everything else, and is hard to notice when it appears on screen, especially since you are suddenly being attacked before it is clearly visible. With the B&W art style you have created a limit for yourself. You don't have as large of a pallet to work with to differentiate the icons from the beings. I don't work in B&W myself, so don't know what to suggest, but I think that for the system to work, you will need to find a way to make the icons stand out more as something separate.
I went to the next one and befriended them as well. Again, knowing how it works I was able to do it, but even knowing what to look for, it took time to process what the symbol was and what it meant. Over time I could see getting used to it and it will be easier, but for new players, they just blend into the rest of the being too much for the fast paced attacks coming at you. I died once and was close to death a second time when I befriended it. Thinking on it, the thing that most stands out to me is the exclamation marks above the head, the symbol to befriend, and the head/hat are all close together and slightly detached from the main body. They all kind of blend together as part of the being. I think if the head/hat was more attached to the body, that would help. The double exclamation marks could be reduced to a single one, and possibly moved a bit further away. The other option would be to make all of the befriending/action symbols have something about them that really sets them apart from everything else. They need to be recognizable at a glance, both as different from anything else on the screen, and from each other.
I like the art style, and think it works well for the game. Now that I know how the befriending works I really like it, and that you created such a system. I think it just needs a bit of tweaking of the display a bit to make it easier for new players.