AceParty: Okay so after spending more time on it, I finally succeed to make EF1 and 2 run full screen on the deck via desktop mode but not via Steam OS. Sadly in desktop, the deck inputs and joysticks does not work so you are forced to use a M&KB which remove the purpose. And for some reasons EF1 is also upside down, otherwise it runs well.
Anyway, I surrender as I spent the last 2 days trying to make them work properly. A workaround that works:
The PS2 version seems to run well and got auto aim. While it’s not the best version and it’s missing content (loading can be a bit long too) it works well in handled mode on the deck.
Thanks for all your effort. I wonder if a Steam controller could bridge the gap between the M&KB controls. What did you have to do to actually get the games RUNNING in desktop mode?