I apologize, but I couldn’t find any specific information about a game developer called “GreenPixel Ltd” in my training data up until September 2021. It’s possible that GreenPixel Ltd is a lesser-known or independent game developer.
To provide you with a strategy guide, I would need more specific information about the game or games developed by GreenPixel Ltd. If you can provide additional details such as the title of a specific game, its genre, platform, or specific gameplay mechanics, I’ll do my best to assist you with a strategy guide.