Author's note:

Castle Awesome is a remake of the ASCII games for the MSX -The Castle and Castle Excellent. The games are exactly alike in their mechanics and objective, with the only differences in the design of the castles themselves:
The Castle is simpler and more action-oriented, while Castle Excellent has the harder puzzles.

There has been a Castle Excellent for the Nintendo (renamed Castlequest for the western public) which has received less than glowing reviews; that version has not been added yet, though it might be considered as a future addition.

The game mechanics are simple and easy to learn.
Metroid it is not:
Raphael carries no weapon and has no special abilities aside from his unusual jumping style and very deep pockets to carry the keys he'll find around the castles, and you'll have to rack your brain to use these skills against therange of obstacles on your way. It is not an easy game, even with the additions included on this remake.. Be prepared and good luck.