Re-painting a wall? If i have brown walls. And I own about a gallon...

If i have brown walls. And I own about a gallon of not here over paint. The walls were painted nearly 2 years ago.
If I paint the walls with a roller. But don't walk perfectly to the ceiling and floor. cartridge it. etc...
Would the wall look bad? will it blend?
Using Tetrion as a wall finish?
Answers:    it probably wont game
but if you paint one wall from corner to corner you wont be able to communicate
What color should I paint my bed room?
It will end up looking close to ****