This was really simplistic and had charming cartoon graphics. The spaceships were really cool looking, and I like the toon outline shader you put on things. I think you could have a compelling game here, given more time.
I think the most pressing issues with it come from a lack of information. The first time I played I wasn't aware that I could move the camera up and down the path, and it wasn't clear to me when and where I could build towers.
I generally liked the graphics. The outlines made a lot of the details pop, but it would have been nice to see a bit more texture consistency. (The grass is very bland, but the rocks and ships are very detailed). I'm not sure if this was a bug or not, but I found that once I placed the first tower I could no longer move the camera.
The usage of the theme was apparent, but in my opinion could have felt a bit more "Ancient" and a little less "Technology" ^_^ Good work one this!
I think the most pressing issues with it come from a lack of information. The first time I played I wasn't aware that I could move the camera up and down the path, and it wasn't clear to me when and where I could build towers.