This feature is very important for those of you that need to create huge outdoor levels. Set fog_start = 0.8 * clip_range and fog_end = 0.9 * clip_range and you won't notice any fog closer than 80% of the clip_range. All the geometry above 90% of the clip range won't show up, allowing you to remove / add terrain, wmb entities, etc on the fly - the player won't be able to see anything..
 
 

Ent_purge, ent_preload, ent_frame, ent_cycle

These instructions work for terrain too. Didn't I tell you that you can create huge levels with A5? Adding terrain and removing it from the world (and from the video memory) has never been easier!

Multiple distributable resources

If you have sold your game and want to sell an add-on or to offer a patch for it you don't have to send the whole package again. You can even split the game files in several resources: sprites.wrs, models.wrs and so on and when you want to change all the models in your game you will only need to overwrite models.wrs.

Collision detection

The new collision system works better than the old one; it uses the variable bounding box of an entity for collision detection, instead of the fixed hulls that were used until now.