Can you recommend some games that would be good for two players on one PC?

Double Dragon.

Candy Crisis

It is free and open source and two people can play at the same time using the same keyboard. And it is a hell of a lot of fun.

What you’re looking for is called “hot seat” games.
Super Tux Kart is a favorite of mine. You can hot-seat with up to 4 players if you have USB controllers. I think you can have two players using keyboard controls, but I haven’t tried it.

You don’t know Jack.

I like sports simulation games and one of my favourites is the Tiger Woods golf series. You can play with one or two people and just like in real golf, you take turns to play each shot. Golf on a computer is much more fun than real golf.

I got my fiance to try out civ last night. She said she liked it but it was too much to take in at once. (her first strategy game) I’ll def have to check out the rest of these games, thanks for the suggestions.

@downtide Same with tennis