Steam gives you an option on each start to either run the game by itself or by a developer-provided config tool (mistakenly referred to as a Controller Layout/Configuration Tool for some reason; ignore this and run anyway). You must run this tool the first time on Deck.

Game runs perfectly on Deck after you run the developer's configuration tool, which Steam provides as an option on each run (see my config note for further details). As the first Deck report says, you need to either de-select the "Black Bars" option or select the option to run in Windowed Mode. If you de-select "run in windowed mode" and the "black bar" option, and switch to DirectDraw 5, the black bars move to the bottom, making it easier to view the screen if you're like me and like to rest the Deck on one's belly or pillow in bed.