Beautiful pixelated style, great icons and enviroment. Are these 3d models displayed at a low resolution with post processing, or plain pixel art? Looks good either way.
I liked the tectonic and star fragment abilities. Nice way to spice up the clicks a bit. If you got a lot less stamina, the tectonic deals more damage and it charges every 3 clicks or something, there's some potential puzzle-ish gameplay here.
Personally not a big fan of the stamina-based rounds with upgrade tree genre. IMO the rounds don't add much. I'm clicking back and forth between the main gameplay and the upgrade tree when they could easily fit on a single screen. I'm missing the satisfaction of seeing an upgrade become available right as you gather the last requirement. Plus too much menuing. However, as far as Nodebuster-likes go, this one is pretty well done.
The effects are satisfying. But the main gameplay got a bit stale by the time I reached Tier 3. I'm curious what sort of idle upgrades you are planning like you replied to another comment.