What are some alternatives?
When comparing LEGO Worlds and Photon Robot, you can also consider the following products
Minetest - Minetest is a near-infinite-world block sandbox game and a game engine, inspired by InfiniMiner...
Nybble - An open-source robotic kitten 😻
Voxelands - The Fun-Focused Free Software Voxel World Game.
Personal Robots - Discover a new toy robot every day
Terasology - Terasology (started under the name Blockmania) is an open source project started by Benjamin...
Aibo - Learn the basics of MBA in less than 24 hours via messenger