Just because you think its good does not mean everyone will like it. Everyone has a different opinion and likes different things. Your group members might not like SCP games or are inactive. I recommend to advertise your game because it will reach out to a wider audience and you can hopefully find some people who enjoy SCP games and will play your game in particular.
There are plenty ways to “advertise” your game using no robux at all. You could send your game link in the popular group walls or friend random people and ask them to play and invite their friends. You could give players rewards for inviting their friends. These are some of the ways you could advertise.
Get investors, the game is well made but there isn’t really much to do. Also you should probably optimize the game more so it would be easier for lower end PC players.
Also, just because you have a group doesn’t mean everyone in it is inclined to playing it. There may be inactive or just joined for the sake of joining. Updates are one of the best ways to get a player base going, and regular announcements and/or shoutouts are helpful.
I’ve checked out your game and I feel like it’s not fully finished since there is no generally gameplay on what players will be doing or who will they be fighting sorting players. Could you elaborate on your game a bit?
There are many reasons and methods on ways to keep players to continue playing your game, perhaps your game doesn’t have a game loop nor a proper gameplay: you just have to add things, that’s worth playing if your game is (enjoyable) then players will want to spend more time to play around and enjoy it.
Add things things to keep players entertained, figure out ways to make your audience come back to continue playing your game. I’ll try to promote your game around the SCP community since all user’s won’t enjoy sorting genres of games.