This list is largely based on Boston Post-Mortem list of MA-based companies, but I also added few companies that are/were defunct. List includes both creators of casual games as well as traditional video game makers.
Active:
38 Studios – Maynard
Blue Fang Games – Waltham
Cecropia – Lexington
Creat Studios – Canton
Dejobaan Games – Northborough
Demiurge Studios - Cambridge
Floodgate Entertaiment – Cambridge
Funkitron – Boxford
Galactic Village Games – Westford
Harmonix Music Systems – Cambridge
Helixe / THQ – Burlington
Injoy Games – Brookline
Irrational Games – Boston
Magic Hat Software – Westwood
Metaversal Studios – Boston
Muzzy Lane – Newburyport
Rockstar New England (formerly Mad Doc Software) – Andover
Sports Mogul Inc. – Medford
Tilted Mill Entertainment – Wellesley
Turbine, Inc.- Westwood
Twitchy Thumbs Entertainment – Ashland
WorldWinner – Newton
Defunct:
Iron Lore
Stainless Steel Studios


June 16, 2009 at 9:10 p
Add Darkwood Productions to this list soon as they are just starting out in Boston.
June 16, 2009 at 9:10 p
Thank you for the tip!