Game Engines

Refers to the software components that govern the physical properties of the game world, interact with the user, and render images for the player.

Made up of multiple systems (Process Input, Physics, User Interface, Object Updating, Networking, etc.)

These don't know the mechanics of the game, just run the update functions on each of these systems

Allow for cross platform development

First engines were the SCUMM engine (LucasArts) and the Java-style bytecode and VM made by Eric Chahi in Another World

3D Construction Kit, very slow
Shoot 'em Up Construction Kit, for FPS games, extremely limited.
Most games still made from scratch

Unreal Engine (Epic Games)
Quake 3 Engine (id Software)

Based off Unreal Tournament and Quake 3, FPS games drove graphical standards in gaming at the time

Twine: Text adventure games, minimal coding skill
RPG Maker: RPG games, minimal coding
Construct: 2D games in HTML5

Unreal Engine
Unity

An discrete scene displayed on the screen, showing the given inputs by the player.

Read Input
Update Game Entities
Run Physics
Render Graphics

Runs 30/60/n times per second to give fluidity

A snapshot of a period of time at which frames are shown, single floating point numbers that make sure everything is run consistently.

1/framerate

Third party software that provide specific functionality, such as a physics engine or sound software.

Typically several are plugged together inside of a game engine.