There was a favorite TD of mine as a kid from Warcraft 3 called CUBE Tower Defense.

This game is very similar to yours, creeps spawn from a spawn point, move through the map to a base.

One aspect of this game was that the enemy creeps had to move through the map hitting specific waypoints along the way.

This created a dynamic where the player could build towers around those waypoints to construct a maze. Given travel times and various pathing, players could create areas where creeps had to wonder through multiple times. This created a “kill zone” and allowed players to have more personal solutions to the game.

This game is wonderful, thank you it.

The foundation you have for it I think could easily adopt this type of gameplay allowing for some pretty cool levels.

As a player progresses through the levels you could introduce this concept, enabling enemies walking on platforms to their waypoints with the pretty cool new path finding feature you have.

Combined with the existing concepts of roads and portals, you and players could create some really fun levels/custom maps.

Food for thought: this other game had a different solution to players blocking the pathing of creeps; The creeps fought back. Not sure how this would play out in this game, just an interesting thought.

Thanks again for providing hours and hours of gameplay.