Natural Defense is a game developed by Sergio Arroyo and Daniel Elvira in Unity3D engine. It is a bullet hell shooter focused on upgrades, with fast paced levels. The player will get upgrade points with each enemy he defeats, becoming stronger each game until finally being able to overcome the final boss.
The setting of the game is inside the human body, more specifically inside a blood vessel, where an infection is taking place and viruses are trying to enter the body. This game however, does not try to be scientifically correct.
Control
At first we implemented a simple mouse-only control scheme where you moved by accelerating with the left click and shot with the right.
However, it was not long before we realised that you couldn't properly aim and move at the same time. This was a huge restriction for the type of frenetic gameplay we were aiming at. This led us to abandon the idea of being mouse-only and integrated the keyboard as the movement controller.
Enemies
There are three types of enemy you have to face:
ADN points
When the player destroys a virus, it will explode leaving behind a set of colour pellets. These can be picked up and will grant ADN points which can be spent in upgrades.
Upgrades
A white cell tries to single-handedly defend the body from the viruses. At first it will not succeed, but by upgrading the ADN chain shown in the GIF below, it will become powerful enough to beat the strongest of all viruses.
Boss Encounter: Ebola Virus
After surviving through the first three levels, this worm-like virus will enter the stage and will slither around slowly. That is, until the player shoots it.
With each successful hit, the boss will divide, growing a new head where the cut is and therefore leaving a new worm capable of moving by itself.
The player must keep dividing the worms, but he should be wary, as the shorter the worm, the faster it moves.
If the player shoots a worm that only has a body piece left, the head will turn green and change its behaviour. It will now act like a mine, moving extremely slowly towards the player and activating if he gets too close. When this happens, it will start rotating and launching basic viruses around before disappearing.
Music
Music song "Radioactive" by Waterflame [www.waterflamemusic.com]
During gameplay, the player might take a lot or very little time to advance a level, so the song is divided in different loops which will not continue until the player completes the level. This way the music always goes at the same pace that the player is playing.
Conclusion
The game came out quite short, and needs more levels and different boss fights. It also needs a lot of playtesting and balancing on the upgrades and difficulty curve, which is pointless to do with the current length. Unfortunately we have moved on to another projects and this will stay as a concept prototype.
Video Gameplay
