LoL, sorry. misread... Tried LCTRL+ESC, on Windows 10, it brings up the start menu and moves app to the background; the arcade cab is running Windows 7 though, so it may work better.
BTW, I installed it in the cab to do a test run; game runs buttery smooth.
Push comes to shove, I can resort to AHK scripting to get it to do what I need it to. Thanks again, Dene!
Edit: I managed to get it to run full screen at startup by making an AutoHotkey Script and compiling it to an executable for testing. The script runs the executable, and enters a tab keystroke to make the window fullscreen, better, but still not as clean as I could get through native fullscreen switch at startup. I still can't figure out the command line switch; I've tried entering the switch several different ways (Spellrazor.exe -fullscreen, /fullscreen, fullscreen, etc. nothing seems to work; It always opens in a window.)