Interesting take on the 'nodebuster' format. Only two things I didn't particularly like:

I don't think that the "enemies drop energy pickups" upgrades are at all interesting, and often times they completely eliminate the efficiency and time based aspects of the game. It's not always bad to completely do away with that aspect eventually, but if you do it in a lazy way like that and also there was limited struggle with efficiency in the first place, it doesn't feel as good as it could if you had multiple ways to solve it.

Not enough content, and I feel as though the levels could maybe be better diversified so that some upgrades would be better than others. In the early stages for example, if you made it so there's a really sparse level, it could punish the people who went all in with just movement speed upgrades rather than any efficiency upgrades etc. Perhaps some enemies would work as well, with different tactics required to defeat long range ones, etc.