The firm said that the teaser, which has received complaints for its low visual quality, was based on outdated technology.
"The demo was, for certification and testing reasons, about a 2 month older build than the final 'what you will play when you get it home' version," said community coordinator Chris Priestly.
"I think you'll see that the game is noticeably better at launch."
BioWare had previously said that the full game will run on Mass Effect 3's engine.
The title will receive a day-one digital release on PSN this week.