You're in a race against the Viking hordes in a randomly-assorted tower of numbered blocks, and must arrange them in order from lowest at the top to highest at the bottom. The size of the blocks gives you a visual cue as well, since the higher-numbered blocks are larger and hence should be at the base. Finish your tower before your opponent finishes theirs, else the mighty Viking Axe destroys your own tower and the game is over.
Each turn you either take the numbered block that's presented to you and use it to replace one in your tower, or chance it by taking the top face-down block and either using it once it's revealed or discarding it and losing your turn. Replacing a block with what you are given is the only option in this game, you cannot move blocks around in your tower. An extremely tall curtain (!) blocks your view of your opponents tower, so you're never quite sure how far along they are. Oh they'll tell you that they're almost done, but they lie!
The game starts out with a range of blocks numbered from 1 to 50, then reduces that range as you progress through each of the eight levels. Be the first to properly arrange your tower's structure and watch your happy little squad destroy the Viking tower with a cannon blast! You can also score bonus points in each round by placing sequentially numbered blocks adjacent to one another.
Analysis: Tower Blaster is a very polished game with classic gameplay, and its few number of levels ensures that you play just long enough to enjoy yourself without getting too sick of the cutesy voices of your tiny "army".
One could always spice up the basic formula with "special" blocks that have different effects, or playing against different opponents with different skills (the downloadable version actually offers this feature), but the game as it stands is a solid, short, and sweet online diversion that doesn't disappoint.