The "believable" adventures of an invisible man? Maybe that just shows a good sense of irony. The game works on its own little logic and trying to grasp it ranges from hard to impossible. At one point the otherwise invisible player character can get a disguise and walk around wrapped in bandages, but the NPCs don't seem to react in any way to him nevertheless and some even ignore him as if he were still invisible. This is where any remaining believability just disappears.
The walkthrough says I can't go into the pub dressed as a patient because none of the patients have any money. I bet that's why the "room for wealthy patients" was empty in the hospital. It's not a good sign when the walkthrough is the only place where you can find the reason why the game world behaves as it does.
The puzzles are really obscure - there's often only one solution that's not very well hinted. The final puzzle involves doing something to an item that's not mentioned in the room description or anywhere else. I'm not seeing any way someone would guess the solution to that, even if the walkthrough talks about it being a "cliché".
The premise would have had so much potential the game just barely scrapes and throws the rest away. You have to be alone to carry things or to do something to the environment to keep people from freaking out or noticing you. A lot of opportunities for cool puzzles with this setting.
[..]
Nothing is on sale.
(the locksmith)
The locksmith doesn't seem interested.
The locksmith has a very peculiar business model there.
I tried to pick up a puppy, but the game thought I tried to take the sun. Easy mistake to make, no doubt.
The bedsheet is tied to nothing.
I wonder what the bedsheet will be used for?
You can't, since the door is in the way.
Repeated a million times. What is this, the 1980s?
Almost every location description lacks the direction where the player first entered the room. You can't assume the players always remember from which direction they came in for the first time.
After an anti-climactic ending I'm left with a bad taste in my mouth. The main character is repulsive and the game assumes that either the players share his sadistic tendencies or that they are willing to roleplay the part. That's not how it works -- I'm not that keen on inflicting pain on a puppy to get my revenge on a guy I know nothing about and who is with all likelihood much more likable person than the player character.
Many games suffer from thin or non-existent characterizations. At least here the main character has some personality, even if it is so repugnant that it makes playing the game a nauseating experience.