The Xbox 360's online Xbox Live Arcade gains two more with the addition of Hexic 2 and Ecco the Dolphin this Wednesday, August 15.

Following up the addictive Xbox 360 HDD pack-in Hexic HD, Hexic 2 expands on the color-matching, shape-forming original with new pieces, different formations, and two-person multiplayer in both online and offline flavors. Developed by Carbonated Games with the involvement of Tetris creator Alexey Pajitnov, Hexic 2 will consume lives sell for 800 Microsoft Points ($10). Along with the announcement, Microsoft sent over 40 new screenshots.

Originally developed for the Sega Genesis, Novotrade's underwater adventure Ecco the Dolphin features online leaderboards and enhanced graphics on the Xbox 360 in addition to its bizarre sci-fi narrative. Previously released on the Wii's Virtual Console at 800 Wii Points ($8), Ecco the Dolphin will be available on Xbox Live Arcade for 400 Microsoft Points ($5). For a better look at the game, check out our assortment of Ecco screenshots.