Boulder Dash-XL
12 Achievements
200
Millionaire
Collect a total of 10.000 Diamonds in Arcade Mode.
15
How to unlock the Millionaire achievement in Boulder Dash-XL - Definitive Guide
While it looks like the number is 10 with a decimal point, this is really 10,000 diamonds. This is cumulative throughout Arcade Mode and considering you usually need somewhere between 16 and 70 diamonds to collect for each levels 'exit' to unlock, you should be close to this by the end of the 100 levels. Unfortunately, there is no way to see how many diamonds you have collected unless you write down the number at the end of each level. If you die on a level, as long as you let it go to the point where you can restart, the diamonds you previously collected will be added to your count. Also, you can use Puzzle and Retro mode and those diamonds count as well. (Thanks to Turdboi and his Misses for the confirmation that it is cumulative through all 3 game modes).