Moai-kun

Build Dates
An ID string listing the build version and date can be found at the end of the PRG ROM: MAST891020 A similar ID can be found in many other Konami games.

"MAST" means it's the "master" version of the game, and the numbers represent the date. So, this build was compiled on October 20, 1989.

Unused Screen Scrolling
There is an unused level feature that enables horizontal screen scrolling, making the level two times bigger! Interestingly, it seems to be fully functional; big levels can be made with no problem, the exit (but not the start) can be placed on a larger area, and the sprites do not disappear when they're offscreen.

You can test this screen scrolling on Stage 3 using the following Game Genie code:

LOSTVYLA

Note: The level will be impossible to complete!

Unused Block
ID: 09

This block is also functional. Its intended use was to hold up any gravity-affected blocks, while enabling you to pass through them. Hence, there is a two-way arrow graphic on it. They are affected to gravity, and can also be destroyed. Boulders cannot pass through them, and if enemies attempt to pass through, they get killed.

Unused blocks behaviour
The falling platforms that fall when standing on them for a second, and the springboard seem to behave like other gravity-affected blocks. When a block is destroyed directly underneath, they will fall until they land on something. The falling platform falls faster than all other blocks and can actually delete some if they land on the same spot. Also, the falling platform will not fall when stood on if there is a block directly underneath.