Methods to improve AI?

[eric-ycw]

The enemy AI isn't too good now. They get stuck often, don't attack the player and such. Is there a clear method to prevent those easy kills, like jumping onto a box and killing them, with no difficulty at all.

More information:
#464
#344

Update with suggested methods:

1. Flee - This should always be a last-resort option with other methods do not work to attack the player
2. Jump - When rat A cannot proceed any further to player B, and B's Y coordinate > A's Y coordinate (player is on a higher area than the rat, e.g. on a box), activate jump, which means add velocity to rat A towards player B to attempt to reach B and attack. This is so that players cannot stand on a foot tall box and fire on enemies that do nothing.
3. TBA