Starting from v2.0.0, network play is possible on CPS2HD.
Right now, it supports wifi buddy mode only and future update will have online battle mode.
For Wifi Network Play (AD-HOC mode), both players need to be under the same wifi network.
(if you have "Tethering" capability, you can enable it and have other phone to connect to your phone :)
1. Enable wifi from the phone setting and launch CPS2HD.
2. Select "Network Play-Wifi Buddy".
3. Select "Player 1" or "Player 2"
Player 1 -> select "Connect".
Player 2 -> Ask player 1 and enter his IP address.
4. Load the same rom
Frameskip level is set by the player 1 at the beginning and can't be changed at runtime.
If games run slow, you can adjust frameskip level at the option setting.