This update brings the requested feature of little upgrades that are unlocked when rising in your player Level.
To keep track of your current progress, open the Info Area and then Personal Progress where all your player levels and completed games are recorded.
Reaching level 5 will unlock a new unit for each civilisation. Reaching level 10 will unlock a modified appearance of the respective hero unit.
The unlockable Units:
Academy
Halfling Scout: A weak cavalry unit available early on in the game.
Bastion
Orc Spearman: An infantry unit that may be recruited alongside other orc units. It features slightly more hitpoints but no ranged attack.
Castle
Zealot: A magical unit that may be recruited alongside mystics. Zealots cannot heal but their ranged attack bounces off their first target and hits an additional enemy unit.
Refuge
Glister Fairy: An additional fairy unit alongside Sprites which features a weak ranged attack instead of melee combat engagement. It cannot fertilize plants but it may summon a shower of celestial projectiles onto a target area.
Ziggurat
Gnoll Pikeneer: An alternative to the Gnoll Bruiser. It's got a higher attack range but no blunt damage.
Necropolis
Skeleton Rider: Skeleton riders can be recruited in the same Building as Death Knights, but they cost no gold and no rare resources.
Happy playing!