Self-publishing is, in some ways, liberating. Housemarque has more creative control over the game, when it's released and how it's marketed. But it's also perilous. The company has chosen to focus on technology and gameplay over marketing. Its core strategy is to make the best game it can, and hope that enough press, streamers and fans pick it up and enjoy it to help make it a hit.
Of course, there will be other efforts. It's partnered with a video team to produce a "making of" documentary in the vein of Indie Game: The Movie. It's signed a deal with Sony to make the game a PlayStation 4 exclusive, which assumedly comes with a financial reward, and the chance to showcase the game to a captive audience at PlayStation Experience. Nonetheless, the press team for Nex Machina is essentially a guy with a desk, and its marketing budget is pretty much paying that guy's wage. I've seen how one person can help make a game a success, but I've also seen that same person fail to persuade gamers to care about another.