It does ramp significantly, currently the highest score anyone has sent me is 1.1m Wave 47. There are plans to add additional depth to the game that will allow for getting through some difficult stages however I felt that getting the core game loop out there for a demo was the best step, then build on the feedback. I also think the majority of games shouldn't last TOO long as its more of an arcade like experience, with outliers of course. You will have an at-a-glance look at your total towers of each element type so you can upgrade appropriately (23 physical towers, 8 magic, etc)
Greatly appreciate you giving it a try and your feedback is on point.