The current amount of players seems to be quite low hindering profit and happiness of players.
If you advertise it would be a win-win situation as the company will receive more players = more purchases = more funds.
For the players it would help with easier matchmaking more friends and more competitiveness.
I suggest that you could use these advertisement methods:
- Obtain more good reviews - Cheap - Lots of views
- Banners - Cheap - Lots of views
- Get popular youtubers such as pewdiepie and tobygames to play the game - Cheapish - Lots of gamers interested in these youtube channels.
I would assume that advertising with youtubers would probably cost around $100 each one.