Thanks for the interest and the question.

I didn't use an engine to make the game... But I sort of ended up making my own engine (-ish) for these Nintendo-style roguelike games. Well, a sort of engine that probably nobody else would want to use lol.

Here's a brief history:

• Wrote core engine in C for Nintendo DS
• ported to Android by slapping on a Java interface layer (game now becoming like Frankenstein's monster)
• ported to PCs that have Java and a "sprite" graphics library installed 

For future games, it makes more sense to use an established engine.