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Making Gameplay more Engaging by using Animated Cover

Players standing still most of the time is boring for them, but from their perspective also the most efficient thing to do. Animated cover can turn the most efficient gameplay into the most engaging and enjoyable gameplay.

Robin-Yann Storm, Blogger

February 25, 2015

12 Min Read

Standing still at a piece of cover and shooting at everything until it's safe to move might be the most efficient gameplay for players, but it may also be very boring. Can we make the most efficient gameplay also the most engaging gameplay? 

By using animated cover, the player cannot stand still for long periods of time, and the most efficient way to play would be to move around more depending on how the animated cover is shaped and animated. Animated cover does not completely disappear like destructible cover does, but is predictable while still facilitating movement. This achieves the goals of having the player be more engaged and the game being more enjoyable. 

If you only have 2 minutes to spare, this video will explain why this project was started, how it was made and what the results were. For more in-depth information, you can read on below the video.

The testing environment

I built two levels for Half-Life 2: Episode 2, with the Source engine from 2007, and decided that if this animated cover system works, then it shouldn't require a brand new pipeline or specific unique features from the game I build it in. Also, a single level designer should be able to create, test and iterate on this system.

This means there should be none of the following: 

  • NPCs who might tell you to 'run for it' or 'keep moving'

  • On screen text to prompt the player into doing something

  • Programming tasks that take valuable time off the programmers in a team

  • Direct explanations of what the level is before it is given to testers

  • Next-gen graphics that some engines might not have


With those features out of the way, the first level has an environmental tutorial where the player has to use the basic mechanics of walking and shooting to progress. After the tutorial the level introduces 2 pieces of animated cover. The second level introduces 2 more different pieces of animated cover. With both levels, the cover is first shown to the player, and later used by the player. 


The players were 20 individuals, of which 10 of them would play through the two levels with the animated cover, and 10 of them would play through the two levels with the static cover. By comparing the amount of movement between those two groups, a conclusion could be found on how much animated cover can improve movement and engagement.

The animated covers


A pop-up is cover that moves up and down from the ground. The player can crouch next to it, blocking their line of sight and assault range, but it will go down after 10 seconds. The pop-up cover is always placed with an A and B variant. They look and operate identically, but have a timer offset. A and B should never be down at the same time, or else the player has no cover at all.

When A is up for 10 seconds and B is down for 10 seconds, B will move up. When B is up for 2 seconds, A will move down and stay down for 10 seconds. This then repeats forever. Sounds complicated? This gif explains it visually:

These pop-ups succeeded in moving some players forward. If the cover in front of the player goes down and there is a piece of cover in front of them that is still up, most players will move to it to stay alive. However, the pop-ups do carry some hefty requirements with them: 

  • There always needs to be another piece of cover visible when a pop-up goes down. If there isn't any, the player will panic and frantically run around trying to find safety.

  • If the Pop-ups are positioned so the player is moving towards the enemy, then some players will hesitate or move backwards.


A really large rotating piece of cover that continually spins at a set speed. It is huge and breaks both the line of sight and assault range of the player and AI. The players can stand next to it, but the cover will rotate away, so they will have to keep moving to stay within the safety of the cover. 

The Rotators were a huge success. The players' line of sight and the line of sight of the AI was consistently broken, fixed and then re-broken. Because the AI is trying to get line of sight on the player and the player on the AI, there is a constant battle of movement that engages the player to the combat at hand.


Fans rotate and can deflect some bullets, but they do not completely block the line of sight or assault range of the player or AI. There are fast and slow variants of the fans. The fast one sits in a circular base and will kill the player on impact. The slow one has a flat base and will not injure or kill the player. The different bases were used to make the player understand which one they can walk through safely and which one is off-limits.

The Fans had little effect on the player. While the fast spinning and inconsistent bullet deflecting is fun to look at and play with, there isn't anything stopping the player from sitting at one spot and continually shooting until everything is dead. Fans can be fun, but in the end they do not function as animated cover as they do not engage the player through movement.

Sliding Sheets

These are large flat surfaces that slide on one axis to block the line of sight and the assault range of both the player and AI. The sheets hang from a bar and travel in a continuous and straight line, making it easy for the player to understand where they are going. Players have to run along them to maintain an accurate base of fire, or can run behind them to stay in cover. 

The Sliding Sheets were the most successful of the animated covers. Both the AI and the players moved around more because of the necessity the sliding sheets created. The sheets are very big, with little space in-between them, making the cover big and the assault times small. Instead of the player standing still for a long time, shooting for a long time, and then standing still for a long time, there is a 'short burst' type of gameplay: The player will fire and dodge, then run with the cover, and then fire and dodge again. 

Changes in static cover behaviour

In the levels there are sections of static cover after animated cover. Some players who had used animated cover became more active at the static cover as well. These players had become used to the movement required of them to use the animated cover and started using that movement even in areas that did not require them to move as much.

Small design changes have big player impacts

Over the course of making these two levels and four animated covers, there were many tiny adjustments made to make sure the animated covers worked well, such as:

  • Pop-ups had to have a visual base so the player would know where they would appear.

  • Rotators had to be slightly submerged in water so they did not look like they were scraping on the ground. 

  • Fans had to have a slow and fast variant, or else the player would simply walk past them or into them.

  • Sliding sheets had to have: 

    • A large bar to signify their course and direction.

    • Only specific areas they could be crossed at or players would run wild and confuse themselves.

    • One missing sheet in each line so slower players could still move through.

  • Some animated covers broke the line of sight, and that can confuse some players on where they are supposed to go. My solution to this was to make the animated cover areas linear, though design and art focused solutions can be researched for non-linear games.

These tiny adjustments had large effects on how players approached, reacted and used the cover. As far as I know there isn't a basic ruleset for these animated covers as of yet. This means animated cover should be carefully thought through, iterated on, and implemented well, as both developers and players are not yet familiar with them from many other games.

Impact on AI behaviour

There were also some happy accidents discovered during testing. Such as that the AI started to move more as well. During level construction I simply put the AI down next to cover, placed nodes on the ground to make sure they understood where the floor is, but I did not explicitly tell them to move to new cover if their old cover was gone. Luckily, the AI of Half-Life 2: Episode 2 seems to scan for cover. If the cover the AI is behind disappears, they will automatically run away to find new cover.

With the AI and the player moving at the same time, the engagement and energy of the gameplay is much higher. But this does require the AI to scan for cover, and move to it. This isn't a feature that a single level designer can create, and thus the extra AI movement is more of a happy accident than an actual feature of animated cover.

Overall results

  • Animated cover can force players to move more and be more engaged with the combat.

  • Breaking the line of sight is the best way to make a player move, but it has to be done with caution. The level designer needs to think carefully about how to convey the right path for the player, so they do not get confused.

  • No static cover should be placed in the vicinity of any animated cover, as players will step away from the animated cover and stand still at the static cover.

  • Some players will move more even in static cover areas, after they have used animated cover and have become used to moving more.

  • The size, timing, direction and shape of the animated cover should not change during its use or it can confuse the player.

Comparatively between the static cover players and the animated cover players, the animated cover players moved more overall. Players looked at the changing geometry in the levels and acted on instinct. The most efficient thing to do in the levels was to move a lot. Moving a lot was more engaging than standing still most of the time. For these players the most efficient gameplay became the most enjoyable and engaging gameplay.

Future research

This small test with preliminary results of animated cover mechanics looks very promising, but it wasn't perfect yet, and there are many things that can be tested for further research.

Narrative settings

Is it possible to make a large amount of different animated cover that makes narrative or environmental sense? Walls that pop in and out of the ground may function well for gameplay, but they make no narrative sense in any setting apart from a training centre. 

Larger & more diverse testers

These levels were only played by 20 individuals, all who are familiar with games in general. There were both players who were very experienced with FPS games and players who were very inexperienced with FPS games, but all of them were generally familiar with games. To see if this system is viable for mass consumption there has to be testing done with a larger and more diverse group of playtesters.

Other game genres

This system was built for an FPS game. There are also opportunities for its use in a wide variety of other games and genres. For example:

  • In the Civilization series there are mountains which cannot be traversed, and they always stay put. What if the mountains moved every few turns, so that the player has to think ahead and calculate the best course for their army? Or rivers that changed course over time?

  • What about an RTS game in which large ridges can both appear and disappear over set periods of time?

  • A stealth game in which you can break the line of sight of guards by holding on to or moving with animated pieces in the environment? Assassin's Creed used walking groups of monks for this, but is it also possible to do this with animated environments instead of NPCs?

Multiplayer versions

These levels were made for single player use. Is animated cover also a viable system for multiplayer games?

  • Does animated cover require a large amount of programming work to function in small or large scale player battles?

  • Could animated cover be useable for competitive games like Counter-Strike, considering split-second reactions are the norm?

  • Would this system be useful for games such as Battlefield 4, where large amounts of moving parts and systems in the environment are the norm?

  • In World of Warcraft there are raid bosses with moving killzones and moving safezones, such as in the 'Hanz & Franz' encounter. Players seem to love that encounter, and it is in a massive multiplayer game, but these mechanics are only used to pit players against AI, not other players. Is this for a design or technical reason?

Contact info

The results I have had so far seem very promising, but I also think there has to be a good reason I have not seen animated cover being used in a wide variety of games. If you have used animated cover before, or tried using it, I would love to hear from you! 

If instead you like what you have read so far and would like to pursue animated cover as well, send me a message! I'd love to work together and try to test these systems in a wide variety of genres, to see if animated cover can improve engagement, enjoyment and player activity in many more games.

I can be contacted on twitter at @RYStorm or by e-mail on RobinYann.Storm(at)gmail.

Special thanks to all my testers, and Mata Haggis, Brenden Gibbons, Joachim Holmér, Elwin Verploegen, Tino van der Kraan & Tina Kalinger for feedback and editing on this post.

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