great questions! All future updates are indicated on the store page. This way we are very transparent with what we are doing. We are not a big studio, so we can't really gamble on updates like the big studios do. So instead we made sales goals: we sell that many games = new update with that content! It would be bad for all of us to go bankrupt over update gambling.
As for the easter eggs, we decided to put everything into the story of the game, wich is a lot more content than in the first game. That being said, a couple players told us the same thing, and we will adjust for future big games.
And yeah, can add those. Will do in patch 1.1, the first sales goal update, that we are well on our way to get!