The best replacement for lua is python.

The best alternatives to lua are rated as following:
★★★★★  python
★★★★  javascript
★★★  c++
★★  perl
★  lua
★  luajit
★  tcl
★  python speed
★  objective c
  scheme
  squirrel
  lisp
  angelscript
  pypy
  luac
  actionscript

Your alternative for lua is not listed? Suggest!
Speaking about lua, one probably shouldn't forget about ogre.

Other search terms related to lua and their ratings are:
★★★★★ ogre
You have in mind a companion for lua and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of lua in all years. Click on graph for more.
lua
python
javascript