descriptions of entries checked and either incorporated to keywords and inspirations or redundancies removed

entries/thunder_engine.md

@@ -2,14 +2,12 @@
 
 - Home: https://github.com/eprikazchikov/thunder
 - State: beta
-- Keyword: game engine
+- Keyword: game engine, 2D, 3D
 - Code repository: https://github.com/eprikazchikov/thunder.git
 - Code language: C++
 - Code license: Apache-2.0
 - Code dependency: Qt
 
-Lightweight game engine for creating 2D and 3D games.
-
 ## Building
 
 - Build system: QMake