go to the game local files right click on AlienShooter.exe and properties then go to compatibility and disable full screen optimizations then run the game if that didn't work run it on compatibility mode either on winxp service pack 2 or 3 whatever that works the best for you.

• the first way is by disabling the steam overlay and it may not work for all the people,
  simply just go to the game properties by right clicking on the game in the library.
  
• the second way to fix this is by disabling vsync on Alienshooter.cfg but it brakes your hud it makes hp bar and experience bar frozen so you don't want that.
  
• and the third and the one that works the best is by using dgvoodoo2 a great tool I use for older games.
  

  dgVoodoo 2 is a graphics wrapper that converts old graphics APIs to Direct3D 11 or Direct3D 12 for use on Windows 7/8/10. Fixes many compatibility and rendering issues when running old games on modern systems as well as enabling the usage of various overrides and enhancements.

  official site for download [dege.freeweb.hu]

extract the files in your game folder or you can choose the game local files in the app.
head to the directx tab and change the videocard to Geforce 5700 ultra, you can change other settings if you want to, now save and run the game, everything should be running smoothly.












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if the resolution broked just change it to stretched, keep aspect ratio.

so we come to the end and I hope you get the best result of this fixes, this is the most I can to support our gigachad russian developer that binged joy to our childhood :).