ReadProcessMemory returns TRUE or FALSE for success.
You send your byte array to it, as well as hProcess,lpBaseAddress,nSize,lpNumberOfBytesRead. The last one (lpNumberOfBytesRead) can set to NULL.
If true, it puts the bytes of memory into byte[] to sent.
Then, you can cast the byte[] into an int.
People generally create memory classes to handle all the different they might want to read, instead of just byte[].
Casting isn't limited to integers either. If you have a class identical to the one in the game, you can read the byte[] from the game and cast it into a class object.