The gameplay itself is great, but one great drawback.
However in my opinion being not able to play the adventure mode again in the same account is really depressing. The adventure mode is the only mode which the game is based on a turn-to-turn mode, i.e. you play one turn and your enemy play one turn. The arena mode, which is the mode that you can play after finishing the game, is a fast-paced game mode which you compete with both the enemy and time. Although it is also a great mode, there are times that I really want to play the adventure mode again. However it is really ridiculous to open a new account with a different name. In addition there is a high score table for the adventure mode indicating your rank, if I cannot play it again with the same name, my name will be under someone [under the default characters! how sad, the default characters get an A grade ._.] forever. Why do I need to change my name for playing the adventure mode once more? Wouldn't it be better to let the user play the mode again as a bonus adventure. There are items that are collected in the adventure mode which make you stronger in battle but you can only take 3 each time, which is very similar to another Popcap's game named Insaniquarium Deluxe. Though Insaniquarium Deluxe DOES ALLOW you to play the adventure mode for millions of times as a bonus adventure, with more features like a bonus stage after each level and all pets(similar to items in bookworm adventures) are allowed to be used even in early levels.
If the adventure mode is not inaccessible after finishing once, I will rate this game much higher than what I rate it now - perhaps even a 9.0.