Celtic Carnage was PAWed, so yeah, you’ll need to play it on a Spectrum emulator. It’s part of a great series of pseudo-historical games by Ian Brown.
Time Quest… That’s a pretty early Spectrum game… so, yeah, it’ll be an interesting experience to play.
You can play both instantly online, by the way…
Celtic Carnage: https://spectrumcomputing.co.uk/playonline.php?eml=2&downid=41749
via https://spectrumcomputing.co.uk/entry/6800/ZX-Spectrum/Celtic_Carnage
Time Quest: https://spectrumcomputing.co.uk/playonline.php?eml=2&downid=43464
via https://spectrumcomputing.co.uk/entry/7109/ZX-Spectrum/Time_Quest
…but a real emulator is more reliable and provides a better experience.