itch.io

Thanks for reaching out. I was thinking maybe adding a unit to each faction that benefits from being in water. For example, a siren for the Beastmen. 
I think the centaurs and leafshooters are a bit too powerful despite their weaknesses--mostly the latter--due to their ability to shoot twice. 
Other units, especially melee units, could also synergize with each other, similar to units in The Realms of Terranor. 
For the campaign, difficulty selection might be nice--maybe add some modifiers or have easier/harder ai. 
For more advanced suggestions, perhaps you could have a sandbox mode where players can create their own maps or have randomly generated levels for replayability. Multiplayer can also be a more ambitious goal to pursue. 
These are just some ideas I came up with, but please feel free to decide. 

I made an account just to comment on this game; I really liked it! I have a bunch of ideas for future content, but overall, I hope to see more from the dev in the future.