Rovio's latest addition publishing adventure is the fiendishly tricky word game Word Monsters. Developed by Raketspel, this free-to-play puzzler blends wordsearch gameplay with gravity manipulation, creating a game that demands fast thinking and forward planning.

You have to find all of the words in each of Word Monster's tile puzzles. Each round has a theme - one may have you searching for animals, while another will be spent locating girls' names. This does make things tricky at first, as you are unfamiliar with the words the game uses. But by the time you unlock higher level challenges you'll be familiar with the game's limited vocabulary.

Discovering a word by tracing a line along it will make it vanish, and cause all the letters above it drop down, changing the layout of the board. This means that you need plan moves well in advance, as it is it easy to swipe yourself into a corner, leaving no way to escape.

While puzzles can frustrate, there are times when your anger will be directed elsewhere. On small screens the tiles are very fiddly to manage. Too often we found ourselves missing the desired word because we couldn’t see what we’d highlighted. With only 60 seconds for each puzzle, and your three-star rating based on speed, this can lead to moments of fury as you find yourself cheated from your reward by the poor interface.

The other huge flaw is that the game can accidentally generate words the game won't. You would be surprised how angry you can get when you are up against the clock and being told that Eric isn't a boy's name.

Word Monsters is a charming idea for a game, and with seven free word sets it is certainly worth trying if you are a word puzzle fan. However, unless you're are playing on a large screen and don't mind seeing the same words again and again, then you might find the technical issues and narrow vocabularly a bit frustrating.