One. *Any
PC device, I'm sorry I didn't specify.
Two. Yeah, multiple antiviruses like to conflict, unless it's one big one and one small (focused a specific type of thing), for example Avast and Malwarebytes.
Three. When you open SMBX2, you get a Launcher. Let me show you around.
LEGEND:
- Info Screen - here you can view information about episode which has been chosen.
- Episode Select List - in this pop-down list you can choose episode from Worlds folder in SMBX directory which you want to play.
- Player 1 Character Select List - here you can choose as which character you want to play as.
- Play Episode Button - launches SMBX engine to play chosen game with no need to go through menu once again.
- Save Slot Select List - in this pop-down list you select on which save slot you want to play; it shows you if save slot has been ever started and how many stars were collected if there are any.
- Delete Button - delete a chosen save slot.
- Player 2 Character Select List - if there's second player who wants to play, he can choose the character to play with.
- Launch Editor Button - starts PGE (SMBX2 editor).
Four. About speed, it is comparable to 1.3 and 1.4 speeds. It can be slow for you due to fact that X2 has a lot of new items, which it needs to load. Your specs can also make a big difference, especially with PGE.
EDIT: Also, back to multiple antiviruses. They gonna eat your RAM and processor power. Consider this.