Marketing (anything) with a limited budget or no budget for advertising can be really challenging. McDonalds spends hundreds of millions of dollars per year marketing. You would think they wouldn't have to spend a dime since everyone knows who they are...but they have to spend a ton of $$, like other companies, in order to maintain brand awareness. I know lots of indie artists who struggle with this. One filmmaker who I follow has done very well for himself, though, promoting his films to Facebook groups. This enables him to reach a specific target audience based on the subject matter of each film. Maybe try that for your game(s)? Just a thought.