I like the game concept. It's hard to tell how to sneak around enemies. I suggest giving enemies a suspicious state when player is close to being detected, so the player knows to back off before alerting the enemy. Most modern stealth games have this feature.
In the tutorial, it was possible to trigger the safe while in the inventory.
After scrolling down while reading a selected inventory note, the next selected note is also scrolled down immediately, which may cause it to appear blank if the note is shorter than the previously selected one.
The player's attack feels sluggish. I suggest shortening/removing the wind-up time, and letting the fist extend faster. Metal Gear 2 is a good reference for this type of game.