At least an altimeter, a tachometer and a magnetic compass. The instruments in the current cockpit look somewhat erratic or non-functional. And there's no compass.
Welcome to World War One Flying!!
Nothing much worked on any of these old airplanes anyway. Many things were always breaking down.
So you will just have to fly without instruments.
It may be that this model is not completely finished just yet, but just like the real machines
of their time, they also had many things breaking down and not working properly. So a pilot must use
his skills and hold on to his "Good Luck" charm
Oh, I forgot to mention, to all new pilots to WW1 flying... you have about 6 weeks to live at the Western Front.
So make the best of it! Good luck!