I read r/gamedev and one of the pieces of advice which crops up often is to market your game early. I didn't do this effectively with Starfighter Arduxim and want to do better with Arduxim Squadron Command. This means I'm spending a lot of time at the moment working on adding tools to the game to make it easy to produce media good for sharing on the web. This work still has an positive impact on the game though, for two reasons.
First, I want a flexible, programmatic UI system for showing various information and UI controls, without having to lay them all out myself. This will be used for UI such as the configuration menu, pilot information, fleet information and so on. By being able to say 'here's the information, display it' I can save time by not having to lay out the GUI myself and know that all the UIs in the game will be consistent.
The second reason is that these media tools can ship with the game so players can use them to record exciting or funny moments and share them. This will hopefully spread the work about the game but regardless it lets people share their experiences with their friends.