Hello. Today I found a cute and harmless bug in the game. You can find and admire them in the <Research> tab, but only if all the towers are not open :)
A bug does not affect the game at all, but a bug is a bug.
In the tree of improvements the next tower will be grayed out, right? So, if you click on the area where you should have a chain of tower parameters improvement, you can click on the icon of this improvement itself.
That is, you don’t see it but you can click (Naturally, you cannot improve).
This works even if you do not see the next tower *
Below are screenshots of this ridiculous bug :)