Virus Strike: Interview with indie developer Neil Ferguson

With over 100,000 apps, the App Store is officially massive. So when you put together a game like Virus Strike, a competition-winning Bejewelled/Flight Control/Tetris/Dr. Mario mashup, how do you go about getting it noticed? In fact, how do you go about getting it made? We spoke to Virus Strike’s indie developer Neil Ferguson.


The Game

Virus Strike itself is a pretty simple concept. Red, green and blue viruses drop from the sky. They keep piling up until you hit the “death” line – if you don’t kill some viruses after hitting the line, you lose.

To kill a virus, you need to direct the colour-coded the anti-viral into the correct colour virus. You can draw a line to direct the medicine, or tilt the screen to affect its descent. Be warned, however – tilt the screen and all the viruses shift in that direction too, making it more difficult to direct. And if you hit the wrong colour virus, it multiplies, firing viruses over the screen and messing up your perfectly-laid out virus-scape. Eep.

Luckily, you can manipulate where the virus falls in the same way as the anti-virals, meaning you can move viruses of the same colour into one place. If viruses of the same colour are touching and are hit by an anti-viral, it establishes a chain reaction which destroys all the viruses in the chain. I imagine it’s a bit like how curing small-pox felt – especially as you watch your score jump up.

The Interview

Where did the idea come from?

I came up with the idea for Virus Strike about a year ago. I’d been playing a physics-based game called Linerider, as well as Flight Control. It occurred to me that combining a line-drawing physics-engine with a match 3-type game might be fun to play, so I had a look through every single puzzle game in the App Store to see if anyone had done it. It took me hours – several days, in fact – but I couldn’t find one. Only then, when I knew I had an original idea, did I start developing Virus Strike.

You cite Bejewelled and Flight Control as inspirations, but how did you come about working out the gameplay dynamics and variables for Virus Strike?

I did a lot of prototyping to try and figure out the specifics of the gameplay dynamics. My wife, who’s a journalist, helped me a lot here. She instinctively had a sense of how to create a game narrative for the user and she played the game slightly differently from me, which was useful.

I pretty much ran everything past her and we did a lot of brainstorming together. We’d often head down the pub for a ‘meeting’. Then I’d stay up late prototyping our ideas until 2am and wake up my wife to test them.

I tried four colours, instead of three, as well as bigger viruses and different speeds, and went for the combination that best made for a game that was easier pick up and play. However, I probably will introduce more colours in the future, as well as different virus-sizes and speeds. The great thing about the App Store is that it’s quite easy to release new versions of an app.

What’s the structure in terms of personnel over there? Just how many people does it take to make a game of this calibre?

I am the sole programmer (and the architect, designer, video creator, website developer and MD of the company). A friend, Russell Moore, did the graphics. Donna Ferguson, my wife, did the PR and marketing and helped with the testing and designing the game. The music used in the video was created by someone called Kevin Macleod, hence the reference, but I’ve never met him – he gives his music away for free on his website So overall, it really only took one person (me!) with a bit of help from family and friends.

And how long did Virus Strike take to put together? At any point was it radically different from the final product?

It took about a year. But this was because I developed it in my spare time. Most of the time I was prototyping to develop the specifics of the gameplay. It was never radically different from the final product but a very progressive process. I didn’t know what the end result would be when I started; all I knew was that I wanted to produce a match 3 game with line-drawing and a physics engine.

Once the game has been created, where do you go from that? What’s it like to be an indie iPhone game developer?

It is very difficult for indie developers to get people’s attention without being featured in the App Store – and I didn’t have any budget for advertising my app. But my wife wrote me a press release when I launched Virus Strike which did pretty well. I’m pretty lucky in that she’s a journalist so she knows how to write a good story and to come up with angles that will get other journalists interested. We paid $20 to get the release distributed by PRMac and it was well worth it – it got picked up all over the place, and many sites simply copied and pasted in the press release in full!

I also entered Virus Strike into a competition specifically for indie developers that I found on Facebook called Wiley’s iPhone App Challenge, and to my surprise, it won the grand prize! I got around £600-worth of prizes, which is great, but the fact that I can now say it’s an award-winning game is the most important benefit to me.

I think being an indie developer is a good thing though. I found I could use this to my advantage as journalists respected this fact and were willing to give the game a chance. Once they’d played it, the game usually did the convincing!

What was the hardest obstacle to overcome in developing the game?

Once I’d figured out the basic game mechanics – the line-drawing, the colour-matching and the physics-engine – the biggest problem I faced was structuring my original concept into a challenging game that was easy to pick up and play.

I think it’s important to have an idea of how long each play of the game should take, and how challenging it should be. It needs to get more difficult, but at the same time it’s also got to be fair – the players need to feel like it’s their fault that the game was lost. And there needs to be a sense of progression as the game goes on, so players feel like they are accomplishing something as they play more games – whether this is a higher score or another type of reward.

One of the most problematic things for me was figuring out how the game should end. Unlike Tetris, it doesn’t make sense for the viruses to pile up right to the top of the screen, as it becomes impossible to play at that point.

I introduced the ‘death line’ to stop this, but I didn’t want the game to end abruptly as soon as the viruses crossed the line. So, after a lot of testing, I decided the game would enter ‘Alert Mode’ once viruses piled up over the death line, and that mistakes would be costly at this point. You’ll know from playing the game what I mean!

There’s definitely one stand-out game from the industry – Angry Birds. What’s your opinion?

I think Angry Birds is a great game – but it definitely needs more viruses! Seriously though, I think Angry Birds is very well-suited to the iPhone. It has a physics engine, a simple but strong name and is very addictive. It’s also very easy to pick up and play for a few minutes when you have spare time. I tried to do the same with Virus Strike.

Finally, do you have any tips to make me better?

To get more points, send the wrong-coloured antibody to viruses at the beginning of the game to create large groups. Draw horizontal lines above the multiplying viruses to contain them. Tap the screen as soon as you’re finished with a line to get rid of it so it doesn’t interfere with future viruses. Don’t forget to tilt the screen to make viruses roll down the lines faster. If you’re over the death line, isolate antibodies by drawing circles around them if you are in danger of them hitting the wrong colour.