User blog comment:Bovell/UPDATE: Battlefield 3 demo not yet confirmed/@comment-3062440-20110422181411/@comment-1439572-20110427194829

"same engine as MW2":

Pedro, you know how many BF games use the same Refractor 2 engine with only minor upgrades/changes to it? Here's a list:
 * Battlefield 1942 + expansions
 * Battlefield Vietnam + expansion
 * Battlefield 2 + expansion + booster packs
 * Battlefield 2142 + booster pack
 * Battlefield Heroes
 * Battlefield Play4Free

See? Using the same engine for a long time is not too bad for a game series.

The gameplay, on the other hand...