The start screen is packed with big chunky tiles that represent all your apps. unfortunately Microsoft made them big and chunky so that users with touch screen devices can hit them quite easily.
The down side to this of course is that if you have a lot of apps installed then only a small percentage will be displayed at any one time.
Fortunately Microsoft have provided a way for users to zoom the Start Screen – when you’re on the Start Screen simply hold down the ‘Ctrl’ key and use the scroll wheel on the mouse to zoom the screen. If you have a touch screen, then ‘Pinching’ will do the same thing.