Touch Detective is not for everyone.
That said, this game plays too much like a 15-year-old point-and-click adventure game. I certainly enjoyed my Monkey Island and King's Quest back in the day, but there have been a lot of improvements in gaming since then.
Touch Detective does improve upon the old model in some minor but significant ways. While older games may have given you a slew of commands to use--speak, listen, give, show, take, use, walk, and so on--Touch Detective uses a simple interface with few commands. Most of these commands are implied and combined into a simple tap to the touch screen. Tap on something you want to touch and touch it; tap on something you want to take and, if you can, you take or try to take it; tap on a person and you talk to them. Tap on an item from your item screen before tapping on a person to show or give it to them, depending on the context.
Another welcome improvement--you won't die a dozen times while trying to figure out "what you need to do next." Unfortunately, the improvement isn't too much better because instead of dying, you'll repeat the same dialogue and scenes over and over. "What you need to do next" isn't always intuitive, even if you're familiar with old adventure game logic--"look everywhere, talk to everyone, touch everything, use every item you have on everyone."
The problem ultimately comes down to the plot hinging on trigger events that are frequently unintuitive. If there were a better flow of ideas or more in-game hints to guide the player to the next thing to do, Touch Detective could have been a great game--and not just to those of us with the patience for old school point-and-click.