>>>*K...Not good, possibly not bad. Surfacing lightly should clean up the sealing ring, a bit of sanding roll work will take off an sharp edges that could lead to detonation. Pressure test to assure no cracks or breaks is a given.

Likely particles caused some valve/seat damage. That looks repairable to me.

Any damage to the pistons means they should be replaced. The risk of a piston ring land being compressed is large, since pistons are cheap I would hone the block and install new pistons and bearings if the bores check out....*EB

*Beats the he** outa me!....*LOL**...