The controls are tedious, making the game borderline unplayable.

A few thoughts: 

• The first click tries to interact with something and that is expected.  The second click should should dismiss the dialog, not try to do the interaction again.  
• Interacting with things seems difficult.  I spent 20 minutes on the first screen having no idea what to do other than knocking out the windows with the wrench.  I could not figure out how to interact with the door--then all of a sudden the screen changed to a close up of the door.  No idea what Ace finally approached the door nor why he didn't do so earlier.  
• A few times I was able to see a close up of the vent, showing the type of bolt I need to match with the socket.  But most of the time I just get a dialog about the weird bolts.  I've clicked everywhere on it and am confused as to how I got it to open before, and why I can't now.
• Hot spots are not always there and I'm not sure why.  Perhaps it has something to do with different cursor types..  As one example, once I got the dog on the other side of the crates, I could not get him to interact with the crate movey thing. No hotspot there.  Eventually it just worked.  As another example, there is no indication that things can be moved on the desk.

Even following some of the walk-through hints on this forum, I'm having extreme difficulty progressing.  The game should not be difficult while following a walkthrough.  

First... I never even thought to hit the glass with the wrench - so I started a new game to do just that.

And laughed my arse off.

Ahem - so, yes - it's odd that Ace stops short of walking up to the door. At some point you must have clicked the hand or the walk icon on the door - to make Ace step forward, to allow him to interact with the door controls.

As for the close up of the bolt in the vents - you need to be standing close to the vent to get that screen to appear. If you're standing away from it, it will just give you the dialogue about the bolts. (I am assuming because the game wants to tell you that you're not standing close enough to see the bolts - similar, I suppose in real life, if you're not standing close enough to a screw in wood - it might be difficult to see).

As for Rooter, once he's on the other side - switching to his "nose" icon - should have allowed you to click on the controls.

As for the items on the desk - yeah, I actually like there's no "hot spot" where your icon tells you something is here to do. Yes, it may be tedius to click and drag every item on the table to just see if it moves - but I think that sort of helps make the game a "just move the cursor around until it turns green" - because that'd seem too easy.

Now granted, several people have mentioned the UI being clunky. I've now played the game (as far as I can) like 15 times now - so even the walk through I wrote may be making too many assumptions based on my repeat plays to keep trying to find odd bugs. So if something's not clear on the Walk Through, by all means, reply in that thread and let me know and I'll update it.