Out of the three, I’d recommend going for Dexter's Laboratory: Deesaster Strikes! (GBA) if you can find it. It generally received better reviews and is considered the most enjoyable of the bunch. The GBC game is decent but not as polished. As for the PS1 game, its 3D graphics haven’t aged well, so it might be less enjoyable. The flash game you’re recalling sounds like it could be Dexter’s Laboratory: The Lab, which was a fun puzzle game with block-moving mechanics.