When comparing Leadwerks Game Engine vs Melharfi, the Slant community recommends Leadwerks Game Engine for most people. In the question“What are the best 2D game engines?” Leadwerks Game Engine is ranked 75th while Melharfi is ranked 108th. The most important reason people chose Leadwerks Game Engine is:
Leadwerks's flowgraphs resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish.
Specs
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Pros

Pro Versatile flow diagram script model
Leadwerks's flowgraphs resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish.
Pro Built-in level editor
Has an acceptable 3D map editor that is easy to use.
Pro Handful of Prefabs and Scripts
For example, you take a model (e.g. torch), add a light source to it, add a particle generator (for fire) and save it as a prefab (one file). Then this prefab can be used to add many torches with fire and light.
Pro Mouse events built-in
All objects/graphics have a mouse events like MouseClic MouseDoubleClic MouseDown MouseUp MouseOver MouseMove MouseOut
Pro Network support
Lidgren Network Library
Pro Path finder built-in
Uses the A* algorithm or pathfinding
Pro GUI
It use a GDI to draw on windows forms. You can use all windows self GUI (controls) for your game like TextBox, Button Label ..., you don't need to install a third party or use an ugly controls.
Cons
Con Very buggy
Leadworks is a not complete, it's a work in progress. As such many parts of the engine are clunky, especially the level editor.

Con Documentation and support are limited for non-coders
The flowgraph editor can be used with free script assets to build games without writing any code, but this is not directly intended or encouraged by Leadwerks.
Con Highly misleading advertising
