Visual Effects = Low - Stops freezes/lock ups
 

Change your visual effects to low to stop the freezing.

The issue is with the explosion, no matter whether its a bomb or a plane.
Changing the visual effects seems to stop the game from freezing/lock up.

Please Sticky this until the issue is fixed.

...and to add: turn every settings to low or off (shadows and grass) and change resolution to 1024 and stutter/flickering shadows/popup buildings/low fps/etc will be fixed.

Hooray!.. the game can be played on its lowest settings possible.. Mmmm..