Hey, thanks for having a go!
Sorry to hear you had issues playing; we are working on improving the mouse and keyboard experience as a top priority, but it didn't quite make it into the 0.1.6 update!
We do highly recommend playing with a controller, it's our primary targeted control method. However, you can indeed fire missiles on a keyboard using Left Control!
Hoping you keep an eye on the game and give it another go once the updated controls are in!
EDIT: Forgot to mention, we should have full remapping available in the next update!