upbeat pike
Much like in any good story, there's a resolution to it all. There's a final piece that concludes the experience. I suggest that after a victory and after you've 'won', players get to walk around the map and mine essence shards that are popping out of the ground with their troops (or maybe even with just their cursor).
This might come off as an odd suggestion, but what it does on a psychological level is it gives the players the experience of LITERALLY 'reaping the rewards' of their victory on their own accord and that's really meaningful and interesting. It's a small detail that players would look at like "Holy shit I actually get to walk around and mine this stuff out of the ground that I worked so hard to get."
Building on this idea, have those essence shard 'protrusions' be placed in the map on generation so that people can gather them EVEN IF THEY LOSE. This reduces the amount that they're discouraged for losing and instead it's seen as more of a partially successful mission. This makes players want to continue to interact with the game (especially in the case of including more permanent upgrades).
Balancing wise, I received 6 essence shards for winning a normal game. So in THAT game, just have those 6 essence shards be divided amongst like 3 essence shard protrusions on the map that each hold 2 shards when mined.
atomic sable