The off-kilter, action-packed treasure-hunting of Borderlands is this week's king of the hill on August 23, propelled to the top of Steam's charts by virtue of a mid-week reduction on both the core game and three extra mission packs released so far. Two of the Stalker games benefited from a similar deal while Victoria II features across three other popular store charts.

Borderlands was something of a surprise hit following its October 2009 release on PC and consoles, at a time when the industry was gearing up for a big spend on Modern Warfare 2. However, good reviews resulted in a loyal following and the production of extra missions: Steam's 66 percent price drop prompted many to snap up the lot for under 10 euros, dollars, or pounds.

Likewise the Stalker weekend bundle packaged the first and third entries to the series in a sub-$10 deal. Based on Roadside Picnic by Boris & Arkady Strugatsky and Andrei Tarkovsky's 1979 film Stalker, the atmospheric adventure has been made even better by free fan-made overhauls such as the Complete 2009 Mod and Complete 2012 Mod.

Paradox Interactive, which runs the GamersGate store, should be pleased as punch to see historical war game Victoria II riding high at Direct2Drive, Impulse, and GamersGate. Star Ruler, a versatile space exploration game, looks like it could become the genre's next big thing as it makes its own chart impact.

Steam (General gaming and own label)
1) Borderlands
2) S.T.A.L.K.E.R. Weekend Deal Bundle
3) Mafia II: Digital Deluxe Edition
4) Mafia II
5) Battlefield: Bad Company 2

Direct2Drive (General gaming)
1) Star Ruler
2) Civilization V Digital Deluxe Edition
3) Victoria II
4) Fallout 3 Game of the Year Edition
5) Civilization IV: The Complete Edition

Impulse (Strategy specialists)
1) Elemental: War of Magic
2) Sins of a Solar Empire Trinity
3) Victoria II
4) Academagia: The Making of Mages
5) Galactic Civilizations II: Ultimate Edition

GamersGate (General gaming and own label)
1) Victoria II
2) Star Ruler
3) Stronghold Collection
4) Europa Universalis III Complete
5) Men of War

Good Old Games (Classics)
1) Total Annihilation: Commander Pack
2) Raptor: Call of the Shadows 2010 Edition
3) The Guild: Gold Edition
4) Gothic 2: Gold Edition
5) Painkiller: Black Edition

Note: Steam's chart is based on revenue rather than unit sales. Data collected on August 23. Links lead to YouTube trailers, gameplay videos, or reviews.