The font part is easy enough. Just set name part of the font properties. For example Font.Name:='Arial';

For the pause thing, one way of doing it would be to have a global variable called Pause: Boolean. And then in your main code loop, have a check to see if this boolean is true, if it is then do not execute the main code, if not then continue as normal. To activate it and deactivate you just need to run a check for a certain key press, such as 'P', and when this key is pressed

Code:
  If Pause=True Then Pause:=False Else Pause:=True;
Just make sure that your key press handler is not inside the pause check code, otherwise as soon as it goes into pause mode, you will not be able to get out. This will not matter if you are usin the Form.OnKeyDown method but will matter if you are using your own keypress handler.

Example

Code:
//Maincode loop

Repeat
  CheckForKeyPresses;
  If Pause=False Then 
    begin
      //All the game logic stuff
    end;
  DrawAllToScreen
  Application.ProcessMessages;
Until Application.Terminated;