Game Progress Update #15

Update #15

Hello world! Welcome to the 15th Dev with Dave Game Progress Update.

In this update I’m happy to say that I’ve got the Missile Zones done 🙂 It still has some rough edges, but these will be taken care of as part of the game balancing/level design phase.

The missiles themselves were simple additions to the existing systems, but I did have to make a couple of changes to things to get some of the associated effects to work properly.

Since the Missile Zone has been the only thing in this update, I thought it might be invaluable if I went a little more depth into how I created the zone.


This is how I described the missiles zone in the GDD.

3.3.5 Missiles

Missiles which fly from right to left, possibly using a laser targeting system to warn the player where the missiles will be flying (Like in Jet Pack Joyride, or Sky Force)

Flappy Vaders GDD

It’s not a terrible amount to go on, so I thought I would take you through my process of how I went from the sentence above to the functioning missiles zone in the game.

Since I had referenced both Jetpack Joyride and Sky Force in the GDD, my first port of call was to Google Images so I could remind myself how the missiles looked and worked in these games, and to get some reference images to help with designing the missile and missile effects sprites.

The above image is from Skyforce Reloaded. It uses guidance lasers to show the player the path of the missile and to give them a second or two to move out of the way. The missiles are red and white, and look well, basically just how you would imagine a missile to look.

In Jetpack Joyride, the missiles attack is again forwarned, but this time it uses floating exclamation marks to indicate where the missiles are coming from. This missiles also look strikingly similar to the missiles in the previous game.

So with this in mind, I set to work in Paint .net with a screen grab from Flappy vaders to mock up how I imagined the missile zones to work.

I used Hitfilm Express to create the below video to demonstrate how I imagined the effects would appear in game.

I dropped the warning markers in the end, in preference of the alert flash and the guidance lasers.

I also intend on adding flame/smoke animation to the back of the missiles, but I’ve not got that done just yet.

Once I had an idea of what I was hoping to achieve, as well as all the assets I’d need, then it was time to open AGK Studio and dive into the code.

Red alert flash effect

The first and most obvious addition with this type of zone is the red alert warning flash. This is triggered at the zone start and remains active until the beginning of the next zone.

It’s another full screen sprite placed over the screen, and the flashing is being done using the sprites alpha channel.

It’s handled in a similar way to the Smart bomb effect, with the addition of a direction variable. So when the sprites alpha value reaches zero, instead of the effect ending, the direction variable is toggled and the alpha value is increased instead.


The missiles were the simplest part to implement. They are handled exactly the same as the other zoneSprites, but have additional movement code in the same way that the asteroids do.

Unlike the asteroids, the missiles don’t start moving independently until they are close to appearing on screen.

Guidance lasers

The guidance lasers appear just before the missile sprite is due to appear on screen, and disappear again once the missile has left the screen.

I had to change the way the zoneSprite depths work slightly in order to make the guidance lasers appear over the top of the rest of the zoneSprites, but underneath the missiles themselves.

Next time

And that’s all for this update. I’m hoping in the next one to have the Missile jammer boost working, as well as maybe the last zone and boost as well.

Don’t forget to follow @DevwithDave on social media to keep up to date with the project, and with any luck I’ll see you all next time 🙂