Hey! First of all, thanks for checking it out :)
When was it first released back in January 2016... I had no development plan. It was just a prototype I had been working on for a couple months, totally just for fun. It was a very rough "game" thing. Oxygen didn't last very long, and it all made using pixel art, which was nice because it's fast to whip together and test. Back then it was also free - definitely didn't feel like it was something worth asking for money for.
You can checkout an early build of the game here: http://cairn4.com/downloads/moonbase-jan20.jar (Requires Java installed on your machine)
(FYI, Tab key opens inventory, walking movement and colliding with objects was pretty bad)
It wasn't for another 6 months or so of development, and the first main art overhaul that the game started getting some attention from players.
Anyways, to address your last point - I think you can start trying to get a following as soon as you have something half-interesting to show people. Having art goes a long away in being able to post screenshots online etc. But even if the game is all temp art ... having something unique/interesting that you can screenshot / record into gifs etc and show people that make them go "oooooh, I wanna try that" ... will help you out.