Nice! No worries, glad I could help :)

Any chance it was „CYB3R HUNT“? I‘ve never played it but saw a post about it here a while ago…

Maybe Antichamber? It‘s a first-person puzzle game like Portal, but based on the idea of the „rooms“ changing as you go through them, so each room basically has its own mechanic to figure out

Sadly not as AFAIK you need to be connected to the same network as the device (at least on iOS)