Propel

This is my submission for the first Game Maker's Toolkit Game Jam, which tackles the theme of dual purpose design. 

Propel is a mouse-only top-down shooter, where you control a small spacecraft in an intense fight against an overwhelming number of enemies, the most formidable of which is time itself. Your health ticks down continuously even when you don't take any damage, counting down seconds to your inevitable demise. The only way to  get more time is to destroy enemy vessels.

To help you in this endeavor, your spacecraft is armed with a cannon, which also happens to be its engine, since being propelled by your own shots is the only way to move (or indeed to stop moving, because we are in spaaaaace...). But be careful: the energy you can use for shooting is limited. Luckily, your ship is also equipped with a shield, which you can cunningly turn towards an incoming enemy projectile in order to absorb it and partially recharge your gun.

How long will you survive?

How does my submission match the theme?

As you can see from the description, most elements of this game's design are dual-purposed. 

The player's aim in the game is to survive for as long as possible in the arena. In order to incentivize the player to take an aggressive approach for achieving this goal, a timer, which can only be increased by killing enemies, was introduced. Instead of a separate concept of health, the game directly uses this timer: successful enemy attacks take away precious seconds from the player, while kills add a bit of time.

Movement and shooting are the same action: there is no way to control the player's vessel other than by propelling (or slowing it down) with its own shots.

Shooting takes energy from a limited pool, leaving the player with  no attacking capabilities, if they exhaust it. The player is not defenseless, however, as they can turn their shield towards opponents' projectiles and use it to replenish their energy pool: if a projectile hits the shield, it causes no damage and grants the player a bit of energy. The shield has a dual purpose for the player, since it both offers protection and gives a way to recharge their weapon. Additionally, since for the shield to absorb anything it actually has to be in a way of an enemy's projectile, the player is forced to take risks and potentially put themselves in harm's way in order to get back their ammo.

Thirdparty tools used

• Game engine: Unity 5 Personal
• 3D modeling: Blender
• 2D graphics: Pinta, Spacescape (skyboxes)
• Sound effects: BFXR (http://www.bfxr.net/)
• Music: autotracker.py
• Font: Ubuntu-R (Canonical Ltd., Ubuntu Font Licence)

For postjam version (in addition to the above):

• Font: Inconsolata (Raph Levien, OFL)

Source code

https://bitbucket.org/TerraPass/gmtk-propel

I promise, my code is much better when I don't write it under extreme time pressure.