The auto-turns item doesn't seem worth it, given that it doesn't buy more in preparation for running out. Other than that, the only things that stand out to me are minor visual things. The button text for "buyTurns" isn't formatted the same way as everything else, which looks like a mistake. A lot of the text on buttons goes right up to the borders of the text, which makes them look cramped. Most pressingly, the timer not formatting the time correctly is a very common issue I see in a lot of small games that makes it harder to read.
In case it comes up again, I just did a quick check of the String class for Godot, and the pad_zeros() function seems like your best option for timer formatting.
I'm not fond of clickers myself, but overall this does at least seem like it's one of the more finished entries. I also like that it has and ending.