If you can see the crankshaft through the oil cap you really got problems.
I'm guessin that the camshaft which is visible is broke, probably due to chain failure. It is amasing that because the valves are verticle that it is possible to drive one right through a camshaft without bending it. I have seen it enough that when we do this repair (not too often anymore as even with used parts its probably most of what the cars worth) we do a cylinder leakage test before we start. If the valves are bent and the chain busted its a bunch of work.
Bosch Master, ASE Master, L1
33 years MB technician