2D & 3D games - What are they?

2D stands for 2 dimensional. You can see if a game is 2D as it appears to be flat (has no depth). Games like Pacman, Metal Slug and Super Mario are great examples of 2D games. 2D games were mostly made on the earlier consoles such as the Sega Mega drive.
                                                                                                                            
                                                                                                                             

3D stands for 3 Dimensional, these games include depth so they don't appear flat. These games appear on the later consoles like the PS2-3 and the Xbox because they are more powerful than the Mega drive and other consoles so they could handle having 3D graphics. Great examples of 3D graphics are the Call of Duty franchise and the Halo franchise.