Another classic game, and this one needs no introduction. Arguably the single game that injected the most excitement into arcade video games during their infancy. Original game: copyright Namco, 1980; this version hand-coded in Flash by Paul Neave.
A fantastic Asteroids recreation from Shawn at Hot Flash Games, and boy does it rock! Very authentic classic gameplay with a serious modern soundtrack that just... ROCKS! Shawn did an excellent job designing the sound for the game, as it contains a mix of classic Asteroids samples and some phat rocking beats.
This is simply amazing. Someone that goes only by the name of Voxel, has created a 3D version of the original Metroid game in Director! By taking the Metroid tileset, he built a utility that allows him to convert 2D sprites to 3D sprites, and then he uses those to build the levels of the game.
Back in the day, Space Invaders, by Japanese company Taito, was one of the coolest games to come along as it was one of the first (if not the first) electronic game ever to offer open-ended gameplay. What that means is that it's impossible to 'beat' the game, the aliens just keep coming at you relentlessly.
Another favorite of mine is this game by Squid S O U P. Snake delivers classic-style gameplay in a 3D Shockwave implementation. Very nice indeed.
Bubbels is a strangely addictive Flash game, like Bust-a-Move, from the Netherlands. There are actually five (5) different versions to choose from.