Rance IV:Missables

Vibrator Morning Walk (Chapter 2)
If Rance has sex with Io twice, she will make Sill walk around with an embarrassing equipment the next morning (new Sill sprite for your H memories). Oddly, this can still happen if you call Io at night in Chapter 6.

Maria's Level God (Chapter 3)
When calling for level god with Maria's group, you will see a different level god sporting his own snazzy variation of the Level God theme!

Losing access to characters in Chapter 6
In Chapter 6, you lose the ability to freely add and remove party members. If there are events that require these characters, you better see them before Chapter 6!
 * Io
 * Maria
 * Julia

H Memories

 * 1) Gal Monsters
 * 2) Sill
 * 3) Level Gods
 * 4) Mai
 * Io
 * 1) Purple
 * 2) Yocchan
 * 3) Sanakia
 * 4) Julia
 * 5) Kanami
 * 6) Merim (You get different CG's depending on your choice on the first night you call her. You can't get both on a single save file.)
 * 7) Maria
 * 8) Bell
 * 9) Feliss
 * 10) Shizuka
 * 11) Ran
 * 12) Alicia
 * 13) Cynthia
 * 14) Tama
 * 15) Becky
 * 16) Leila
 * 17) Athena 2.0
 * 18) Mirror Fragments

Gal Monsters (CG from Assault)
You encounter ones with * limited number of times or through special event. Extra. Tokko-chan (Research Core B1F)
 * 1) Canson
 * 2) Bee Girl
 * 3) Seafood
 * 4) Mountainfood
 * 5) Humming* (2 encounters on Surface Power Area)
 * 6) KyanKyan
 * 7) Ralga* (Buoyancy Staff)
 * 8) Science
 * 9) Geckon
 * 10) Jumper* (one of trio)
 * 11) Blazer* (one of trio)
 * 12) Sailor* (one of trio)
 * 13) Black Nurse
 * 14) Sour
 * 15) MiG
 * 16) Magisco
 * 17) Magician* (seen while destroying the 8 magic columns)
 * 18) Mecha KyanKyan
 * 19) Dragon Girl
 * 20) Goldfish Tamer
 * 21) Lantern
 * 22) Cake Girl
 * 23) Kamikaze* (seen while destroying the 8 magic columns)
 * 24) Ramen
 * 25) Frozen (Defense Core BF4)
 * 26) Sulphur
 * 27) Zashiki Warashi