Is there any way (app/modification) to add floating button to Windows 10, which will be semitransparent and always above an app - even full screen game?

I want to play Medieval 2 Total war on my Chuwi, but to call the In-Game Menu I need to press ESC button, and what tablet it is if u always need to have keyboard with you?

If it's important the game is Steam version, but I have BOX one too, so I can change it...