Portal gun

- works exactly like a portal gun should work.
- high research requirements.
- featuring original codersprites.
- puts our policy on borrowing from copyrighted material to a test.

![portalgun](https://cloud.githubusercontent.com/assets/5390315/4781210/244c3b72-5c90-11e4-9bd9-3c4f2a2a99a3.gif)
![portalgun](https://cloud.githubusercontent.com/assets/5390315/4781211/2e2c2486-5c90-11e4-99cc-e3a42cd9dff8.png)