Duke Nukem Forever, 14 years in development, sits atop the Steam chart for the week ending Monday, June 13 and slides into fifth on both Direct2Drive and GamersGate, while Modern Warfare 2 is bolstered by discount sales.

Duke Nukem Forever, finally clear of a turbulent 14-year development cycle, was far better received on PC than its troubled console counterparts.

Elsewhere, The Witcher 2's sprawling adventure basks in ongoing popularity: it is Direct2Drive's best-seller and was beaten to number one on Good Old Games only by its budget-priced predecessor.

Space Pirates and Zombies continues its mastery of the Impulse chart, while Pride of Nations takes top spot at strategy specialists GamersGate.

Steam* ( steampowered.com)
1) Duke Nukem Forever
2) Call of Duty: Modern Warfare 2
3) Terraria
4) Call of Duty: Black Ops Escalation Pack
5) The Witcher 2: Assassins of Kings
*Based on revenue, not units sold

Direct2Drive ( direct2drive.com)
1) The Witcher 2
2) Call of Duty: Modern Warfare 2
3) Sid Meier's Civilization V
4) The Sims 3: Generations
5) Duke Nukem Forever

GamersGate ( gamersgate.com)
1) Pride of Nations
2) Dead Space 2
3) Europa Universalis III: Divine Wind
4) Red Faction: Armageddon
5) Cities in Motion

Impulse ( impulsedriven.com)
1) Space Pirates and Zombies
2) Galactic Civilizations II - Ultimate Edition
3) Elemental: War of Magic
4) Medal of Honor
5) CivCity: Rome

Good Old Games ( gog.com)
1) The Witcher: Enhanced Edition
2) The Witcher 2: Assassins of Kings
3) Gothic 2 Gold Edition
4) Divine Divinity
5) Arcanum