I played a couple of games last night and spent about an hour flying infantry around to defend my base.  There's more work to be done on the pacing of the game, but it is coming along nicely.

My time playing, I think or hope, helped shape a better vision for a demo or at least a shorter-term goal. I want to create a "skirmish" build. This will be just a few buildings. HQ, farm, water pump, solar panels, and single-level towers. This could also serve as a demo on Steam and for sharing more broadly with an audience that's curious but not ready to commit. 

 The goal will be to fine-tune the first 15-30 minutes of play. This has been my goal for a few months now - but the skirmish mode feels much more focused. Aside from the handful of bugs that need to be fixed and some juicing up of the gameplay, the next big goal is to adjust and tune the enemy spawning. 

Currently, the enemy spawns quasi-randomly around but near the player base. There are "crystals" out and about that are, so far, poorly defined in terms of their role. These will switch to spawning sites reducing the variablity in spawn locations. This will create more consistent pathways to the player base - making it easier to defend as well as make it easier for the player to explore/expand and find the crystals.

Finding and destroying the crystals will stop the enemy from spawning.  For the "skirmish," this will be the goal. For the full game, this will then allow the player to fully explore and develop all the resources on the level - with the goal of making use of some or all of the resource production in future levels.