Following the progression screen UI the rest of UI elements and the gameplay itself were also adapted to different aspect ratios. I should probably explain more details about the last one - the original concept of the game meant fixed position of the camera, with the battle field exactly fitting the screen. And as the mobs spawn beyond its right border, their path to the player base would take much less time at 4:3 aspect ratio than at 16:9. In the first prototype I've compensated this issue with mob speed adjustments, to keep the base reaching time the same at any aspect ratio.
However, with the real graphics it turned out that at the squarest aspect ratio the base take almost half of the screen, and the difference in the distance between base border and screen edge to the widest one reaches 4 times! Simple speed adjustments don't work well at such rates. So now the battle field has fixed size for 21:9 aspect ratio, and at the aspect ratios more narrow only part of it displays at the time, enabling moving the camera to its borders. I've developed three with a half different ways to control that movement, which one is better only time and players will tell, for now there is a switch for it in the settings window.