The side game is meant to earn money for assets in the main game. Since we didn't expect that we would rework it to be so big, we didn't account for all of the extra assets in the kickstarter. So, instead of trying to have another kickstarter or something like that, we decided to make a side game to earn the funds to finish the main game (I paid for the assets for the side game, which is ultimately cheaper than paying for the rest of the assets for the main game).
There won't be any spoilers in the side game! It's just meant to be their relationship after the main game, but it doesn't have any major reference to the main game's plot.