Actually that is not really true,
Koikatsu BetterRepack RX20
School setting
mapping is
school building 3 floors with a few rooms per floor,
a sports field,
a courtyard,
a cafeteria,
a pool
a gym
front entrance (school gate)
Around the school there are 3 icons that appear randomly and allow you to increase your stats
(learning = book, fitness = dumbbell, erotic = pink heart)
events are character driven with stars appearing on the map
side events include sex with teachers
Basic idea, add characters to game, interact with them through chatting to increase their affection level, convince them to join the Koikatsu club and gain score to unlock extra option / positions etc.
Koikatsu Sunshine EX BetterRepack R10
Vacation / resort setting
Mapping is
1 of 3 building to stay in, hotel, sport center or house/cottage like
beach
little town
aquarium
river bridge
light house
house / cottage like
sports center
path way with access to hidden beach (if bought with points)
Around the island are icons that appear randomly to give you topics of discussion allowing you to increase affection quicker when used.
Basic idea is to chat to characters and gain affection and have sex.
Side event is with one local girl/woman
with dlc's new private / exclusive areas are added.
Koikatsu is slightly more story driven and has slightly more mods
Sunshine is more free roam and quicker to get to the H scenes
Sunshine has more character because you can import character from Koikatsu to sunshine but not from sunshine to Koikatsu.
Points are also easier to get in sunshine and give you more freedom in your game play by allowing you to spend them in a shop in town, such as unlocking the hidden beach, unlocking toys, unlocking special services etc. plus it has more minigames and "date options", while Koikatsu requires you to go to the club room before the end of each time period to register your points in the club book and there are new date options with dlc but they can only happen on weekends limiting you time with each girl.
hope this helps and have fun playing.