There's no fixed route, every tower you drop becomes a wall, so you literally build the maze that funnels enemies through your crossfire.
Enemies enter an open field and head for the exit, always taking the shortest route available. Because your towers block tiles, each placement reshapes their path, arrange towers to herd the horde down a long, winding gauntlet past as many of your guns as possible. Just don't fully wall off the exit. Hold the line through every wave.
Maze Keep draws on the open-field tower defense pioneered by browser games in the mid-2000s, there is no fixed path, so the towers you place become the maze the creeps must wind through. It turned tower defense into a spatial puzzle.
Maze Keep is an original free browser game in the open-field (mazing) tower defense tradition, where your placements define the enemy route. Just open and play.