In a yet to be published interview with C&CG, Valve's designer/engineer Robin Walker reveals that it is already working on the second installment of its episodic series of Half-Life 2 expansions. This would also mean that Episode One is nearing completion, of which Walker also revealed it contains about 4-5 hours of gameplay. HL 2: Episode 1, previously known as HL 2: Aftermath is expected to be available through Steam on April 24th priced $19.99, with EA publishing a retail version shortly thereafter.