IDAC CO., LTD offers many room escape games for iPhone/iPod/iPad. Many of them are free, and they all offer a challenge that fans of the genre crave so much.
One small annoyance that is common in all IDAC games is that they are linear to a fault. You must do everything in order. And the game must be absolutely certain that you saw every clue before it will allow you to solve a corresponding puzzle. This can lead to a lot of frustrated tapping. But as you play more of their games, you get used to this and are more aware of it. Therefore, you learn to play the games the way they intend it, and it becomes less frustrating and more enjoyable.
IDAC has an app in the app store that's pretty unique. It's called AppNavi and you can play free room escape games, such as Escape Game: “A Cold and Deserted House,” through it. When you complete one, you send in your score and earn points. As you accumulate more points, you can trade them in for more games. This means you can play quite a lot of games for free.
In addition, IDAC offers some of their games as single apps to download from the app store. Some cost money but others are free. They also link up to AppNavi, so you can send your scores through to earn points. Here are some notable games that offer a good challenge:
Strange House, Dangerous Luxury Liner, Prank House and Snow White are their only 3D games. They look much more professional than the 2D games, but still suffer from the same gameplay faults. They are still enjoyable to play and full of great challenges.
The Drifting Locked Chamber offers a unique setting on a ship. Your ship was attacked by pirates and now you must get back to shore and escape. The puzzles are logical and don't require a lot of guessing.
The Mystery of the Abandoned Factory is quite a challenging game, but doable nonetheless. You have to combine items together, then take them apart again, combine them with other objects, and sometimes even destroy the items to use them. This means most of the items you find have multiple uses, so this game will take a bit of time to complete. It's great fun, though.
The Meddling Shogi Player is challenging for anyone not familiar with Shogi game rules. But the moves of each piece are explained, so you won't be completely lost. It is one of their tougher games, but if you stick with it, it can be quite a satisfying experience.
An Uninspired Man and An Odd Game are two more games worth noting. An Uninspired Man is a bit frustrating because you really need to explore every corner of the room, even places you didn't know you could explore. It's a challenging game, but the puzzles are great and it's a fun experience. An Odd Game is not quite as good, but still worth playing. Like its name suggests, it's the odd one of the bunch. Your clues are hidden on dolls, and paper cranes fly!
There are many other great room escape games by IDAC, and you could spend a lot of time going through all of them. See if you can make it out on your own! But if not, you can read some of the walkthroughs on my site.