Here are some sites where you can download versions of Blast Thru and its parent Breakout:
Blast Thru - v1.11 (10 levels) and other Blast games
Breakout -the original, playable online
Drew Barrymore Breakout - like Drew? Not when you've finished this game.
Smiley's Breakout - cute 3D graphics
Breakout Clones - more clones