Minecraft 1.2.6 Alpha _top_ Download Link -

Released in early December 2010, version 1.2.6 marked the final "Alpha" update before the game transitioned into the Beta phase. It represents the peak of early Minecraft’s charm—a world of neon-green grass, terrifyingly silent Creepers, and the raw potential of a sandbox game that was about to take over the world. Why Players Still Seek Minecraft Alpha 1.2.6

A: Alpha 1.2.6 used a static, bright blue water texture. That is the "retro" look you are hunting for. Minecraft 1.2.6 Alpha Download LINK