Company shall submit the applications to Steam for release no later than the first commercial release of each Application or Localized Version, or if already commercially released as of the Effective Date, within thirty (30) days of the Effective Date.

This should mean that games coming to steam will release on steam first or, if the game isn't new, it will release 30 days after the contract takes effect. This means no delayed releases unless they advertise their game somewhere else first and then bring it to steam later. In short, no advertising on steam and then pulling the game.

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Thereafter, Company shall submit to Steam and Localized Versions and Application Updates (in beta and final form) when available, but in no event later than they are provided to any other third party for commercial release. Company shall provide these copies in object code form, in whatever format Valve reasonably requests.

This means that the developers cannot update games on other platforms before they update the steam game. This should prevent DLC from being delayed as well. The capitalization on words like "Localized Version" or "Effective Date" likely indicates that these terms have an agreement specific definition stated elsewhere in the agreement.