Level-13, is a map pack which contains 'updated' versions of official (MP) maps created by Irrational for SWAT 4. But not only official, any user created maps are also supported (SP/MP). Professional players will find updated spawn points, level design and lightning in all maps provided. There are some minor weapon tweaks, but nothing that will change damage or recoil of any weapon unrealistically. Minor changes with weapons like a little more realistic recovery rate for crosshair, improved zoom, more clip counts (only those that require) increased grenades affect (CS lasts longer and has larger radius, same goes for bangs, stinger do a little more damage).
Menu and in-game screenshots.