Sega's Olympic simulation is once again followed by a super hero combo of LEGO Batman 2 in second and The Amazing Spider-Man in third.
Elsewhere, FIFA Street climbs three places to re-enter at nine, below fellow football title FIFA 12. Batman: Arkham City completes this week's Xbox 360 chart activity, re-entering at ten.
The top ten in full:
1. (1) London 2012: The Game (Sega)
2. (2) LEGO Batman 2: DC Super Heroes (Warner Bros Interactive)
3. (3) The Amazing Spider-Man (Activision)
4. (7) Ghost Recon: Future Soldier (Ubisoft)
5. (8) Modern Warfare 3 (Activision)
6. (5) Elder Scrolls V: Skyrim (Bethesda Softworks)
7. (4) Spec Ops: The Line (2K Games)
8. (6) FIFA 12 (Electronic Arts)
9. (12) FIFA Street (Electronic Arts)
10. (13) Batman: Arkham City (Warner Bros Interactive)
Leisure software charts compiled by Chart Track, (C) 2012 UKIE Ltd.
Watch a trailer for London 2012: The Official Video Game below: