Thanks!
My original idea was to make no interface outside of in-game elements, like they do in Dead Space or so. That's why enemy HP is towers and your HP is guys. But looks like I should try harder to make game info more readable, especially when bullet-hell with bunker blocks come to play. :)
As for changing weapons - it changes cross-hairs (little blue, big red and laser line) and little lamps on robot's back. And crosshairs hides when you have no Attack Points enough.
And yes, 30th level was the last, but now the game is endless. :) BTW, I've just uploaded the last version, which will go to Steam soon. And when it finally be released in steam, I must set the same price on itch.io too. So grab it until 19th, if you want :)