- how can i have an "all systems" to the display menu ? I can have grouped (arcade, consoles,others), or no categories at all, but it is possible to have an "all" category, which list every rom in every system you have configured ?
What I can do at the layout level, is add an "All displays" to the displays menu with categories, so that when you select it you'll see a list of all your displays uncategorized. This won't bring you to a romlist with all your games, but to the list of all your displays/systems.
What you want to do is a romlist that gathers all the roms and systems you have, and this can't be done at layout level (I can't generate romlists in the layout), but Attract Mode allows you to do it: just go into attract mode menu (TAB button), "Emulators", "Generate collection/romlist", here you can select the romlists you want to add to your "all games" romlist. Then you can see this as a Display in Arcadeflow Displays Menu.
- is possible to have categories ? like shoot'em up, and it shows every game listed as shoot'em up regarding its system (for example, it will list axelay (snes), 1941 (mame), ikaruga (gamecube) etc ...)
If not possible, isit possible to do so via filters systeem ? (i'm new to AttractMode ...)
There are many ways to do this, both for single system displays/romlists and for multiple systems displays/romlists.
Arcadeflow doesn't have a "Categories" menu, I can do it and maybe I'll do it sooner or later, but consider that sometimes different systems use different conventions for category names. In my Mame romlist categories are like this: "main category/sub category" (perfect for a nested menu, ain't it?), other systems only show one category, others like GBA show them as "sub category/main category", so using this in a multi-systems romlist will be a bit of a mess.
Another way to have category menu is to create Attract Mode filters for the categories, this is very flexible and works in all sort of Displays. Since you know how your games are categorized then this is usually better than the layout solution.
Last but not least, and this is a feature of Arcadeflow, if you are on a game (like Street Fighter 2 which is a "fighter/versus" category) you can select "more of the same..." from the context menu and automatically filter games with the same category or sub-category, or even year, decade, manufacturer etc.
Or, still in Arcadeflow, you can sort your collection by Category on the fly, without the need to create a filter, and jump from a category to the other with hotkeys or the scrollbar....