Midnight Pool and Blockbreaker Deluxe
If anyone has played these on mobile phones you know the Speccy would benefit from games with their playability. It could be argued that we already have too many Pool games and Arkanoid clones, but I strongly suggest that you try these two games if you haven't done so. Midnight Pool and Blockbreaker Deluxe are simple but a lot better than any similar games I've seen on the Spectrum. I'm not talking about the graphics, but the movement, playability, themes, options, etc.