Atlantis Tower Defense Game

With my main computer out of action, I am forced to rely on my less powerful laptop to continue adding to my folio. Being a fan of tower defense games, I have decided to create assets for my own hypothetical one, as a low poly folio piece.

"Atlantis has fallen. Merpeople of Isla have slaughtered most of your citizens and soldiers, and determined to erase your history. Refugees are fleeing to remote underwater outposts where you, a last remaining Chief Strategist Pathfinder, are tasked to defend against the incoming armies."

My objective is to create five towers - Spear Turret, Mine Deployer, Bubble Net, Biter and Sonic Boomer - and five enemies - Small Fry, Optio, Chariot, Recon and Centurion  - that share a similar design style.

Posted below are WIP images, in order left to right:
TOP: Biter, Mine Deployer
BOTTOM: Spear Turret, Bubble Net