Rat monsters now follow the player.
Pool ball monsters now follow the player. Moreover they are able to follow the player around corners using the game's new pathing system!
Many types of monsters (marines, menaces, slivers, lampreys) are now part of a "Hive Mind". Once monsters part of the hive start attacking the player, there is a two second delay before they actually start damaging the player. The "hive delay" is indicated by the green rectangle on the lower left hand corner of the screen. Once the player is safe for 3 seconds, this delay resets. So if the player is on the boundary of a bunch of monsters that are part of the hive, the player can chip away at the edges safely.
However if the player tries to fly through all the monsters, the 2 second grace period will be used up and the monsters will damage the player.
Many monsters now have a "personal delay" X (usually X = 2 seconds). Once they hit the player with a warning shot, they only deal damage after X number of seconds. This resets after not seeing the player for 3 seconds.
Certain monsters only hurt you when you are smaller than them. For these monsters, now when you are the same size as them, there will be a red letter S on your screen (to show that if you shrink, you will need to worry about them).
Most basements and cellars now have a waypoint in their treasure room.
Added grid labels to buildings in the Mylantis Top City. This makes it easier to find the House of 5 Lampreys and the Secret Farmhouse.