Bubblewords was a cute but unremarkable game - from a stream of letter bubbles, place them in the grid to create words. Valid words disappear (Tetris/Bubble-Bobble sytle), keep going until the grid is full.

Bubblewords created a novel problem, the STB had 1Mb of memory, games were typically 300k, the dictionary file we needed to validate words from the grid was around 1.2Mb.

The solution was to compress the dictionary data and keep it compressed on device. The key being each word in the dictionary is typically a small change from the word before it. By storing words as deltas on the previous word a huge saving could be made. In order to achieve quick look-up it was necessary to index the compressed data so you could enter the data "near" the word you wish to validate. You then run through the compressed data, needing only a one word sliding window of decompressed data.

The compression solved the memory problem. Alas on first run the game stalled for 17 secs whilst it assessed the grid. Optimising word look-up down to the order of millseconds is another story...