Pets vs Aliens Prologue

Pets vs Aliens Prologue is a story-driven implementation of the classic board game Othello a.k.a. Reversi. Unbeknownst to mankind, little farm animals must fight an alien invasion, represented as successive Othello matches. The story is narrated in "lullaby" rhymes (following the style of a classic children’s book) gradually presented between matches. Technically the game is implemented using the BIFROST* Engine, which allows the ZX-Spectrum to display multicolored sprites (i.e. combine more colours than normally possible without colour clash).