Among the highlights for Alien Arena 7.53 are extending the use of VBOs (OpenGL Vertex Buffer Objects) throughout the game to offer large performance increases, improved bot AI, optimized/improved vegetation rendering, new maps, IOM/MD2 rendering optimizations, and a new ultra skill level.
The main highlights as what Alien Arena sent over to Phoronix are listed below. The game for multiple platforms can be fetched from the Icculus-hosted site.
Extended use of VBO for big performance increases
Signifigant improvements to bot AI
"Dm Lights" server option
Improvements to menu code
Improved stats algorithms
Entity definition files
Optimized and improved vegetation rendering
Variety of bug fixes and code cleansing
Two new maps
Optimizations to IQM and MD2 rendering
New "Ultra" skill level
Speed hack detection improvements