The The Lost Levels Add-on for Gunpowder (Windows) has 5 achievements worth 50 gamerscore.
Collect all bonus items in the Lost Levels
Beat Mission LOST-6 with all bonus items without the spark being extinguished by a wagon
Break the safe on Mission LOST-12 right before the flooding water washes it away
Beat Mission LOST-21 with all bonus items, without breaking a single crystal
Score a basket on Mission LOST-23