Hey so glad you enjoyed it! We found the mouse movement really satisfying too!
As for the win condition, there is a progress bar at the top of the screen, and you have to kill a certain number of Malwars to reach the next stage. You also have a health bar in the top left, that if you get hit or run into too many Malwars you die.
Bug spawns are random, and while the Gigabugs should eventually roam into the middle of the map, we will look into restricting their spawn points so they don't spawn too close to the corners next time. Great feedback! Thanks for the play!