1. What is the HUD?
In video games, the HUD ( heads-up display) is the method by which information is conveyed to the player as part of a game's user interface.

2. What is the HUD?
What information can be shown to the player? Here are some common HUD elements. However this is not a definitive list, be sure to analyse the games you play in the future.
Health / lives
Current Score/ High Score
Currency
Time
Weapons/ammunition
Current Equipment: weapons, items, or spells.
Recharge Countdown
Mini-map/ Radar
Speedometer/Tachometer.
Context-sensitive information
Reticule / Cursor / Crosshair
Stealth meter
Compass / Quest Arrow

3. Examples of HUD
Super Mario Bros is a great example of a basic HUD. It displays it’s information with terminology and visually.
Important information is located on the top of the screen. It consists of your current score, currency, the current stage and time left.
However there is no Health bar, it is displayed visually. Grabbing a mushroom increases size. When you get hit you return to default size. Getting hit again looses a life.

4. Examples of HUD Health Refill Health Bar Magic Refill Magic Bar
Other Ammo Type
Current Ammo Type
Current Ammo
Other Ammo Type

5. Examples of HUD
New Objective

6. Examples of HUD
Equipped Magic
Context Sensitive Information

7. Examples of HUD
Subtitles
Audio Log

8. Examples of HUD
Quest Arrow/ Compass

9. Examples of HUD
Changing weapon is another instance of your HUD. On the PC version (Pictured above) you can simply press the represented number to change weapon or scroll using the middle mouse button.
On console you would hold down a button for the weapon dial to appear. You can then use an analog stick to decide you weapon.
Because of this platform of choice can completely change to controls and HUD of a game.

10. Examples of HUD

11. HUD Context
Metroid Prime gives context to the HUD by emulating what the protagonist sees through her helmet.
The helmet can be seen on the edges of the screen. It makes us, the player feel like we’re in the suit of armour.
More information can be given to the player without breaking the sense of immersion because why wouldn’t sci-fi space armour give the wearer up-to-date intel.

12. Examples of HUD
Other effects are also include showing the reflection of the protagonist briefly after an explosion, rain and ice.
These minor effects really sell the idea that you are in a living, breathing world.

13. Minimalist HUD
Within the last decade games have become more cinematic. In order to achieve a more movie-like appearance they have streamlined the HUD and in some cases stripped it out completely. A notable example would be the Dead Space franchise.

14. We can see all key elements such as health and kinesis (Space magic) mounted onto the characters back. Ammo count is projected from the gun.

15. It goes further than HUD elements
It goes further than HUD elements. All inventory menus such as items, maps and mission briefings are projected in real-time. It gives context to game-play mechanics and creates a sense of immersion.

16. Handheld Games HUD
Games have also improved dramatically on hand-held devices aswell. You need to take into account the smaller screens and the fact the players thumbs will take up to a third of that space from using touch inputs. Because of this HUD design on hand-held becomes more important.
The examples above (Jetpack Joyride, Angry Birds and Fruit Ninja) can all be played with a single finger. Notice how few types of HUD element they use.

17. The Infinity Blade franchise is more complex
The Infinity Blade franchise is more complex. More information and button commands are required.
Notice how all the icons hug the edges. This reduces size and makes it easier to place a thumb over.
Some of the icons are transparent as well, allowing the player to see more space.