Stopped Working on Steam Deck
I played a game called Dungeon Antiqua recently on my Steam Deck, which runs on the Pyxel engine. While the game worked perfectly the first few times, when I booted it up this morning, I got this error message:

File "dungeon-antiqua-tmp.py", line 1 in <module>
File "pyxel\cli.py", line 225 in play_pyxel_app
File "pyxel\cli.py", line 211 in _extract_pyxel_app
File "pyxel\cli.py", line 137, in _create_app_dir
FileExsistsError; [WinError 183] File Already Exists 'C:\\users\\steamuser\\Temp (The rest is cut off by the screen size.)

While it's possible this is a problem with the game's code, given the error message I suspect this is a problem with the engine's code instead. 

Just to be sure I've also tried contacting the Dungeon Antiqua devs, but given that they're Japanese I have no idea if they're even going to respond. 
https://steamcommunity.com/app/3198540/discussions/0/6617568006280651821/