Hi Milan, tell us about your app. Drone Invaders is a space shooter game. You control a laser gun turret and have to shoot down all the incoming waves of aliens. The game features various powerups, interesting enemies with a special distinct boss every ten levels. Interesting missions, and daily and weekly challenges give enough variety so that the game is not only about shooting aliens.
Who is on the team? For Drone Invaders it did all the programming, graphics and sound effects. Music is by Kevin MacLeod borrowed under Creative Commons license. For some other game with more challenging graphics I usually contract external designers from websites like 99designs or Fiverr. mfvkvfm7123
How is your app different from similar apps or competitors? Drone Invaders is designed specially for mobile devices. Unlike other shooter games that try to mimic the gamepad, joystick or mouse controls, in Drone Invaders there is no spaceship to move around. This makes the game feel natural on devices where touch is the main way to control it.Tell us more about the design and UI. I have to say I spent a lot of time on the app icon, although it wasn't initially meant for Drone Invaders. Some time ago, while making my other game Gods of Sparta, I needed a nice graphics of a shield. I looked around the web to get some inspiration, and found one tutorial on YouTube how to draw shields. Making a nice shield requires a lot of gradients, shadows and color mixing. I designed it in Inkscape at first and did some final touches in the Gimp. This shield is one of the best graphics I have drawn ever, so I'm really proud of it. Later, when making Drone Invaders, I needed an icon for Force Field and this shield fit really well. After adding a small space-invaders-like alien into the middle, it looked so good, that I decided it would be the icon for the whole game as well.
I wanted to keep the used interface simple, but appealing. For background I added a scrolling texture with stars and nebulas. I have drawn nebulas in Gimp using some tutorial I found on the Internet with a couple of tweaks of my own. The widgets are drawn with regular 9-patch using a simple blue color theme. A great inspiration for the layout of the options was the game Subway Surfers.
What tools did you use for creating the app? As for tools, I'd call it a standard open-source Android stack for making games: For graphics and design Inkscape and Gimp. For sound effects there's a tool called as3sfxr which is really, really great to generate effects and then I used Audacity to polish them. For programming and building I used Eclipse and LibGDX library. I'm doing all the development on Linux, which poses some challenges. For example, I had to use Wine to run BMFont tool to create fonts. Luckily, that worked.
What lessons did you learn building this app? WComing from C/C++ background I did a lot of things "manually" as I was used to do before with libraries like SDL. I learned that LibGDX has a lot of it built in, it just takes time to grasp all the concepts. You can use it as low-level library and create all the UI, widgets, etc. yourself, or you can learn the high-level concepts like Stages, Actors, etc. and use all the widgets it provides. Also, Eclipse is very good and makes programming very productive compared to simple text editors I used before. I will surely use high-end LibGDX for my next project instead of reinventing the wheel again.
What went right and wrong with the development and release? The development was meant to be done in one month, as a part of Ludum Dare October Challenge. I completed it in 23 days, so that when really well. The main problem afterwards were the bugs in the in-app payment code. Google Play offers merchant accounts only from a couple of countries, and mine was not included. So I had to as a friend from USA to create a development account. Unfortunately, I could not log into that account from my country, so I had to build the VPN and tunnel the connection each time I want to check players' comments or upload a new version. This was inconvenient, but the real problem was testing the payments. Although everything would work with fake payment tests, testing with real credit cards would fail. I wrote to Google about this and reply was that I cannot test with my own credit cards. Since my country is not supported for in-app payments I had to find another friend to do the testing for me. Now, I have a lot of friends in various countries, but sending them the code, requiring to build and test for each new release was really painful. I'm thinking that my next game will either be completely free or be payed game without in-app payments because of this.
What were you doing before the app? Ever since I was a boy, my dream was to create games for a living. I wrote my first game for C64 when I was 10 years old. Later I wrote some games for Amiga 500, and PC. I released some open-source games in the past like Njam, Vodovod, Scalar, Abandoned Bricks, etc. Njam is a pacman clone and it's got 50000+ downloads, many users sent levels and some even build custom hardware setup to play the duel games as you can see in this picture:
Some of the Njam players, nudged me into making a more polished, commercial, closed-source sequel, which I did in 2007. However, I was completely ignorant of the fact that I should do marketing, so Njam2 sold in just 30+ copies. The game still sells from time to time, it works on Windows and Linux.
Seeing no financial future, I gave up on gaming and went to create accounting software. In 2013. I got fed up with that, and started again to create games just for fun in my spare time. Accidentally, one of the games for the local market in Balkans became a huge hit, which gave me financial freedom to work on games full time. Drone Invaders is my first game for mobile devices.
Shorter version: I used to develop open-source games between 2000-2007, then quit that to make business applications and got back into game development in 2013. this time making it my full time job.
What are some of your other favorite apps? Although I used to be a hard-core PC gamer, I was really inspired lately by some mobile games: Pudding Monsters, Subway Surfers and Badland. I feel those have great visual design, and right difficulty and balance.
Head over to Google Play to download Drone Invaders now.
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