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From the minute it boots up, the game is already utilizing dual purpose as it uploads a trojan virus into you- just kidding!

The start menu serves 3 purposes. By paying homage to the 2D games Rank S.'s bullet hell mechanics come from, an intractable platformer menu is used to guide you to the game's level. By using a 30 second minigame at the start, the game teaches you controls and mechanics in a tight, focused environment that make them easy to grasp. This is all while giving you something less monotonous to do than click a button and wait for the game to load. In a fully featured game, randomized aspects of the menu level could continue keeping the player interested every time they boot up the game.

Once inside the full 3D level, you are presented with one core mechanic. The N.R.G. system (get it? spell it out loud!) You can use unlimited N.R.G. to shoot and rocketjump your way around the level. But your enemies also have this resource. Enemies use two frequencies of N.R.G. to fight you, red and green.

Fortunately you have a shield to defend against this, but it isn't perfect- you can only absorb N.R.G. into your own system when your shield is tuned to the same frequency as the enemy hitting you, or else it's good night. Your N.R.G. only regenerates when you are recharging it via kinetic energy (this happens when you run) or when you are absorbing an enemy's attacks. No hiding behind walls. You also deal extra damage to enemies of the opposite frequency to your shield's. Maybe you want to risk getting hit to finish off those baddies?

Third-party resources
www.unrealengine.com - Game Engine
soundbible.com, freesound.org - SFX samples, which I later mixed.
facebook.com/freegamemusic - Music
youtube.com, epicgames.com - engine help
autodesk.com - 3Ds Max for modelling
audacity.com - application for mixing, warping and generating music.

Contributors
me :)