Not so much an "alternative" to Wordle as much as "Wordle - the next generation". It's a leap forward both in the layout algorithms (which permit sophisticated shape-filling) and the design of the tweaking interface. It's very unusual to find a programmer who has both the sophisticated algorithmic know-how and the keen sense of user-centered design that Hardy Leung exhibits. He clearly has had an eye on the various warts in Wordle, and has addressed them with energy and determination. I wish him and his project(s) well. Go check it out!