I liked the click and drag power on enemies! It was a lot of fun tossing them around.
The only issue I ran into was that there is often a lot of downtime between new enemies spawning making the early game fairly slow. And the base version of new ability unlocks are fairly underpowered compared to the toss move. I unlocked fire, but it took several upgrades before it felt worthwhile to use.
Overall though, a great core loop and a nice twist on the tower defence genre.