I went through the whole game now, as far as I know. Beyond most of the menus, the game's not really in English: All 8 of the NPCs you can speak to, the pause menu's item descriptions, the save rooms' teleporters' target locations, and an option in the title screen's option menu are all in Japanese- though this last one I'm assuming must stand for "HUD Pics" or "display HUD in-game" maybe, since the config.ini changes a field labeled hud_pics whenever it's toggled on or off. I'm not sure if any of the NPCs' dialogue goes through any changes, so there's probably not that much text to translate should someone be able to.
One of the included text files warns to avoid using save data made from versions of the game older than the 1.03 demo's as it may cause problems. Thought that was worth mentioning somewhere.
If you want to get the gallery which was added in version 1.05 without beating the game, just make a text file containing the following:
... and rename it "game_data.ini", placing it in the same folder as the game's executable.
The gallery's options are similarly untranslated, but I've intuited that left and right switch animations, up and down zoom in and out as it does in-game (though it doesn't always center on the heroine inside the gallery), the melee/confirm button apparently starts the selected animation from its first phase, the jump/cancel button exits, 1 and 2 lets you cycle through different area themed backgrounds back and forth respectively, 3 and 4 make the animations face horizontally left or right respectively, and 5 and 6 toggle the automatic animation option off and on respectively.
shame it's in Japanese. Got something like zoom options and stuff and don't know how to use Them. Also got all 4 level keys and kinda stuck. In main middle room and don't know where to got. Grinded so hard that kill every enemy from 1 lightsaber swing.
I ran one of the included text files through machine translation- it looks like zooming in and out outside of restraints is done with the 1 and 2 keys respectively if you're using keyboard controls, and with up and down if the heroine's been restrained. You can only zoom in as far as the zoom upgrades you've collected allow (i.e.- if you've only found the first one, you can only zoom up to 1.25 times, 1.75 if you've found two, 2.0 if you've found all three).
From the "main middle room" you described (the one with the Lv.2 and Lv.4 doors in the bottom left and bottom right corners, respectively), go through the bottom left. In that area, head to the bottom right to find a Lv.3 door that you went past before you could've obtained the Lv.3 card. When you go through, you'll find a new, bigger area with Lv.5 and Lv.4 doors in the bottom left and bottom right corners, respectively. Hopefully you can figure out that you're going to obtain the Lv.5 card in the areas past the Lv.4 door, and what to do from there.
Dumb question, but what button do you need to push to go through doors? I'm stuck in the first area, lol.
As far as I could tell, there are no doors that don't open automatically. If the door's in the background, it's not meant for you to interact with- all other game elements you interact with by pressing Up when standing near them. The only doors you interact with are presented to you as horizontal things you can walk through. If you're at the very beginning of the game, just walk right- almost all areas that lack walls let you enter the adjacent area. You can open the map with Q, if you're lost- though it doesn't help very much since it doesn't show how the areas connect to one another.
If you come across a door that won't open, you're either missing the appropriate key card (the door has a small color coded label on it matching the card's- green for Lv.1, yellow for 2, red for 3, black for 4, or white for 5), or you need to do something in the area such as interacting with a switch or breaking conspicuous objects. A couple of times you'll need to change from the tank-top and skirt to a cleavage-exposing catsuit by interacting with a changing room- this wardrobe change toggles the doors around you, since you enter or leave areas containing enemies or objects that only have animations for one of the two outfits.