If you're looking for another Ultiverse alternative, Inworld is worth a look. It comes with an AI engine designed to let game developers create more lifelike AI agents and more dynamic game environments. That can lead to more realistic game mechanics and more immersive gameplay. The platform includes tools for character creation, scene composition and AI voice creation, so it's geared for developers who want to make their game more dynamic.
Another alternative worth considering is Dreamlab. This game engine is designed to let developers build multiplayer games more quickly with modern web technology. It lets developers create levels, characters and props with AI models, and it's designed to handle real-time multiplayer interactions. The built-in AI coding assistant and support for web-based development make it a good choice for developers who want to get their game design work done more quickly.
If you want to go full-on AI, Magick has an Artificial Intelligence Development Environment (AIDE) that lets you design, deploy and control AI agents and bots. It's got a visual node builder for constructing code and event-driven response system for quick reaction to changing circumstances. Magick's AIDE is designed to work in a variety of domains, including gaming and cryptocurrency, so it's a good Ultiverse alternative if you're looking for something more general purpose.
Last, Galxe has a decentralized super app with a variety of tools designed to make Web3 experiences easy. That includes the Galxe Identity Protocol for credential management and the Galxe Score system for reputation tracking. The app also includes Alva, an AI copilot for real-time insights and analysis. That could be useful if you want to build digital identity and reputation systems into your game.