Apps similar to Game Builder include Godot Engine, which is free and open source. Other options are Unity, Unreal Engine, GDevelop and LÖVE. Game Development Tools like Game Builder are a crowded field, with more than 50 alternatives for Windows, Linux, Mac, the web and Android.
Rogue Engine is a full featured environment for game development using WebGL. Create projects in an intuitive and familiar 3D environment using configurable components made with TypeScript.
GeeXLab is a cross-platform demotool for 3D programming, demos creation, game development, interactive applications, creative coding and prototyping.
Leadwerks Game Engine provides the smoothest learning curve to take you from beginner to full-fledged game developer. Use the visual editor and the flowgraph system to set up game interactions without code. Use Lua to write your own game scripts.
United States
Free online 3D Game Maker. Make your own 3D games online! Create Games for Web, Mobile and Desktop. Easy to use.
Verus Engine is a modern, platform-agnostic 3D game engine. It is developed using C++ and HLSL. It is based on Direct3D 12 and Vulkan graphics APIs. The code is user friendly and well optimized.
Estonia
EU
Valkyrie is a no-code creative platform that lets designers combine digital assets and create applications and interactive prototypes: where the power of Unity meets the usability of Photoshop.
United Kingdom
Tululoo Game Maker is a complex game creation environment that allows you to create browser based games. The program generates a Javascript code that can be played in web browsers using the next generation web standard HTML5.
HungaryEU
Reality Factory 2 is a next-generation game authoring suite. It combines a flexible, fully scripted game development environment powered by Python with the Ogre3D engine, and supports all major desktop operating systems.
Japan
The only true complete development platform for online games. HeroEngine seamlessly integrates the entire client and server architecture required to operate an online game directly into the development process.
United Kingdom
Pixel Game Maker MV allows you to build up your own action game with no programming knowledge necessary. This engine was designed with the idea of giving a voice to people's passions, allowing them to freely express the game that they have held in their hearts.
Japan
France
