TransPlaySupport
The FAQ answers most of it. If you are still stuck, email us.
My game isn't in the list
Check that the file extension is one that console reads — each console page lists them under Supported files. Archives are unpacked by the app on import.
I only get a black screen
PS1, Saturn and Dreamcast will not boot without a BIOS file; Settings → BIOS shows exactly which one is missing. Disc games need a format that carries track information, such as .cue or .chd.
Translation is missing or wrong
Very small text, or text drawn over a busy background, is hard to recognize. Use the ⋯ menu in-game to set a Translation area over just the dialogue box — accuracy jumps. If a game pack exists for that title, names and tone follow the original as well.
All-Pass bought elsewhere isn't showing
Open the app you bought it in once. As soon as that app refreshes its entitlement, the others pick it up. Sharing across devices also requires iCloud Keychain to be on.
Contact
Bug reports and feature requests are welcome. Telling us which console and which game it happened in makes it far quicker to fix.