Source

The video below shows gameplay from most of the games that were made in Source. Keep in mind that nearly all of these games run well on decades old hardware!

Source Engine was created by Valve in 2004, and it made huge strides in physics simulation, AI, and graphics that were considered outstanding at the time. Despite being fancy for that time, the hardware specifications required to run video games on the source engine was very minimal. While it is mostly used for 3D first person video games, it also has uses in filmmaking. In fact, videos as recent as last year have gone viral using this engine! A majority of the games made using this engine are held in very high regard, with the most notable being Half-Life 2. Despite being decades old, this engine still gets constant use.