Warning... Wall of Text (guess it shows how much I like this game, though xD)
I've previously made a comment of suggestions and such, and after playing a bit more I've found/come up with a few more things (some of which may be planned for post-alpha):
-The option to climb over low walls/fences/objects.
-Changeable difficulty within apartment (Normal and Hard). Normal is the same as it is, Hard would increase NPC detection range, increase speed of confidence falling, and disable the detection circle. If wearing the Blindfold on Hard, sight is completely darkened so that only Rika can be seen on-screen (opposed to Rika and what I assume is 4 feet around her).
-Buyable clothing at a shop within the neighborhood (like maybe on the other side of the bridge), opposed to being unlocked by default. Starting out, only the Casual outfit and Towel would be available, and the rest are purchased, with Yen being earned as 5% of points earned when going Home (or 10% on Hard to reward the extra challenge).
-NPC Suspicion at close range. When in close proximity to an NPC, if Rika does not have Bra/Panties/Socks on but does have dress or shirt and skirt on, a detection circle pops up and fills very slowly, hinting at their suspicion. This can also apply when exposed and walking behind an NPC.
-NPC Hearing. Simply NPCs being able to hear if Rika is masturbating too fast (since fast masturbation would cause moaning and/or squishy noises), which will cause them to move toward the source. NPCs can hear twice as far away on Hard.
-Vibrators that can be equipped within the wardrobe. Will automatically fill up Rika's lust whether she is naked or not. If she reaches full Lust with the vibrator in, she will automatically kneel down to cum, preventing movement for a time while letting NPCs detect her regardless of current clothing. In Hard difficulty, the vibrator will fill Lust twice as fast. Using NPC Hearing as described above, they could hear it if in close proximity and get suspicious (also as described above).
-Toggleable difficulty modifier (separate from Normal/Hard) to make it so the less Covered Rika is, there's a higher chance per step she'll drop her apartment key (it will start glowing 10 seconds after being dropped). When wearing any amount of clothes that prevent detection circle (or suspicion as described above) she won't drop it, but if she's completely naked it would be a 20% chance to drop per step she takes (as an example). After being dropped and recovered once, it won't drop again for the rest of that session.
-More restricting items (similar to blindfold). One I thought of would be ankle cuffs that take the shoes slot, with them on, Rika cannot move faster than a walk. Another would be Handcuffs (only available when Naked and meant for the Key modifier above) that prevent Rika from climbing things (as described above), prevent her from crawling or covering, and make grabbing the Key slower.
-Walk button. Probably don't need explanation here. Just a button to walk on PC opposed to jogging. Using the modifier of dropping the Key as I described above, Walking could halve the chance of dropping the key.
-More Challenge Ideas:
--With a Vibrator equipped, never allow it to completely fill Lust
--Allow a Vibrator to completely fill Lust while completely naked
--Leave the apartment naked, buy clothes, and return
--Leave the apartment wearing only Handcuffs, streak 100m and return
--Leave the apartment wearing only Ankle Cuffs, streak 100m and return