Hi! I think your idea is great, and I don't mean to be rude, of course! This is just my personal opinion on this. The "fake multiplayer" aspect of your game is actually... very noticeable. Maybe some people wouldn't notice, but there's also those who most definitely would notice that they're just bots.
So, I have some tips. Firstly, the bots move very slowly, which they shouldn't at all in my opinion. Considering that your speed stays the same at all times and you can't change it, it's very odd to see them moving so slowly and makes them feel like they're not an actual player. I would reccomend making it so the speed of the bots is the same as the player's.
Secondly, the bots go to the player too much. Yes, I know there is a hostile enemy in the game, but usually the chance of them appearing is, infact, very low. Either that, or their fight happens off-screen. And besides the hostile enemy, it still feels odd that some bots will just completely ignore that there's another bot right next to them which they could attack. Maybe you should make it so that the bots treat the other bots and the player as the same, or attack the person who's the closest, no matter if they're a bot or an actual player. I'm not sure, I'm not really the best at coming up with solutions, so hopefully you could figure something out for that.
Onto my third point, the bots aim way too accurately, aswell as turn way too smoothly. What I mean is that they aim at the player perfectly, which you wouldn't really expect from an actual person. Same with the smooth turning, no one really turns their mouse that smoothly. Again, not really sure about a solution for this, but I hope you could come up with something.
And, lastly (Although this list most likely isn't the only issues that this game has with it's fake multiplayer) the usernames are... weird. Don't get me wrong, I understand not having much usernames to put in, it's just becoming a problem when the usernames don't really sound like usernames anyone would pick. Sure, you can add those usernames in, but you should still add more realistic usernames and different types of usernames. Maybe look at videos, posts, etc. that give people username suggestions, and take some usernames that exist on the internet (Maybe even add your name to have a small chance of appearing, so people actually think the creator is playing the game! That'd be neat.). Random username generators won't really help you, considering they're generators.