I dealt with it. YT video (https://youtu.be/PQXQxFvdX1c)
Despite it calls self 'the best invaders on any computer' I see some flaws: no joystick support . There is some lag by pressing fire key - and that makes hard precise shooting of moving targets.
Anyone likes this game pretty much ? It was btw. published by Budgie UK, sold for 10 GBP in 1994.