Space Invaders
It doesn't get any more old school than this. Space Invaders one of the very first space shooters. Enjoy!

Galaga
Like Galaxian, you control a spaceship and shoot at swarms of incoming insect-like aliens that fly in formation above you and occasionally swoop down to bomb you in a kamikaze-like dive.

Galaxians
Destroy swarm after swarm of invading aliens. One of the first space shooter video games. Click to play the flash version on GamesLodge.com

Donkey Kong
You are Mario and you must rescue a damsel in distress, Pauline, from a giant ape named Donkey Kong. A flash version of the 1981 Nintedo classic.

Pacman
The classic's back: Pacman ! Have fun !

The King Of Fighters
A flash remake of the classic arcade game The King Of Fighters (KOF).

Super Flash Mario Bros
This is a nice flash remake of the classic Super Mario Bros, with an option to play as Mario or Luigi and take on the evil Koopa and his army, through various levels.