In hard levels, the level is generally harder than a normal level but uses the same sort of puzzles and obstacles. and a few diamonds to collect, though not necessary to complete the level, it will increase your rating at the end.
In a normal level there will be various puzzles to solve, such as levers, pushers, boxes, and the newly introduced springboards, etc. There are 30 levels, consisting of 17 normal levels, 6 hard levels, and 7 green diamond levels. The original version (in chinese) was released back in November 9th, 2010.
Fireboy & Watergirl III in The Forest Temple Again is a fanmade game for the series by Fei Cheng.