Ok, so using
hobo1955 's system, I made a list of each map, and each cool feature in each one.
SG1: After refill, evil dogs fill the map (except the corn), also at night the neatherack catches on fire
SG2: You get a nausea effect when you reach a certain block-height
SG3: The water rises around the map OR The heat makes it that you get slowness for 10 seconds after sprinting 20 seconds
SG4: There should be cars added around random spots that explode every once in a while
SG5: When it snows it deteriorates your armor
Ancient Japan: Your hunger depletes faster, because asian food won't fill you up!
Solar Frost: The coldness makes you swing slower
Breeze Island: The heat makes it that you get slowness for 10 seconds after sprinting 20 seconds
Freeze Island: When it snows it deteriorates your armor
Demons Breeze: The heat makes it that you get slowness for 10 seconds after sprinting
10 seconds
Valleyside University: On the football field, you have speed 1
Holiday Resort: The heat makes it that you get slowness for 10 seconds after sprinting 20 seconds
Fortress Pyke: The water rises around the map
Fallen Empire: Nothing
Lost Ridge: You get a nausea effect when you reach a certain block-height
Teweran SG: When it snows it deteriorates your armor
Teweran SG2: The heat makes it that you get slowness for 10 seconds after sprinting 20 seconds
Kharmunrah: The heat makes it that you get slowness for 10 seconds after sprinting 20 seconds
Moonlight Lake: The water rises around the map (except the center)
Wyverns Wake: The dragons spit out ghast-like fire balls randomly
Insanity Cause: The water rises around the map
Survival Kingdom: Nothing
Asia Games: There's a nuke and the map permanently gets deleted from all servers (SERIOUSLY HATE THAT MAP)
Moonbase 9: The loss of gravity thingy
Treacherous Heights: You get a nausea effect when you reach a certain block-height
Rugged lands: You get a nausea effect when you reach a certain block-height
Fortune Island: The heat makes it that you get slowness for 10 seconds after sprinting 20 seconds
Hell Games: wild dogs spawn in the woods after refill
Lost Mine: when you reach the end of a tunnel you get poisoned for loss of fresh air
*Takes breath, and bows*