Original name is かりんとあそぼ！, also remember to set your PC on Japanese Uni-Code. Very good gameplay, with collectible skills and weapons and some very hard jumps.
The game is in English, but there's no text apart from the start screen and the in-game menu.
A very simple game at its core, Kare Kano's gameplay consists of a very limited traditional VN dating sim style, where the protagonist chooses actions for the day that affect his statistics.
You play it like an old first-person dungeon explorer, only with random naked chicks to play with.
The sequel is more of the same, with a more convenient map and animations in some scenes. There's a limit to how long you can maintain the pocket world that serves as your hunting grounds, and losing fights or letting your girls escape depletes it.
You find out that while you were in jail, your homeland was annexed by a feminazi nation and it is your job to form a resistance group to if you lose and strengthening the girl along losing a level. The "Applocale" utility may not work with this game, and you need to run your computer on Japanese.
You can win fights normally or by arousing the girls, by which time they'd allow you to fuck them and teach you new abilities. Do you see this underdeveloped person of legal age right here? A still-yet incomplete (newest version is 1% done) possible platformer/puzzle vore game.
No eroge novels (aka 'erotic visual novels') in this list: there are so many of them that we have made a page just for them.