Is there a way to finalize a game that I already burnt and forgot to finalize?

Uh, I don't think DVDs don't have a concept of "finalize" That's an ISO9660 thing.

Well there is an option in Nero to create multi sesion disks. As well as a box to check to "Finalize DVD (No further writing possible!)" So I'd imagine it may be possible depending how much space is left on the disk. I know to finalize a disk it requires a small amount of space to be left. If the disk is full it will not allow to finalize due to there not being enough space on the disk.

You shouldn't have had the option to finalize...since you would have been burning an image.

I was thinking that if he wrote the disk in UDF format it would give him the option of finalizing or not. But I just noticed that the finalizing box is checked and greyed out. I guess I was wrong!