Earth Warp/Gameplay

Controls

 * Y and N: On the title screen, the game will ask you "Do you want sound?" (a cursor will also flash to its right in both versions); if you press N for "no" the game will play in silence. It will then ask you "Have you played before?" - and for the full effect, you will again have to press N for "no", because if you should press Y for "yes", the game shall proceed to the first of two challenge selection screens (the second one can be reached by selecting "Part 2" on the first one), rendering all except the final challenge skippable if desired (like in Geordie Racer, Through the Dragon's Eye, and Sky Hunter, this is presumably for the benefit of people who cannot complete the game in one sitting). If you choose to go to Part 2 in the BBC Micro version, you must also insert the game's second disk and press Enter before the game goes to the menu for it (providing your DFS is compatible).
 * Space: When a sign of three horizontal lines stacked on top of each other appears in the bottom-right corner of the screen, you shall have to push this key to continue; when you have to make a choice, you must also push it to move the highlight to the next option, and press Enter to confirm it. In the fifth challenge this key serves to select the next empty square on the electronic door panels once the currently-selected one is the right colour.
 * Esc: As in the Acorn Archimedes version of Sky Hunter you can use this key to return to the challenge selector of the part that you're currently on.
 * Delete: If you enter a wrong character while typing in an answer, push this key to delete the wrongly-typed answer then try and type it in correctly.
 * Arrow keys: For the fourth challenge you must use these keys to hop to another rock in the river and carry on the pattern of colours, along with S if you get stuck and have to start again; however, in the sixth challenge, you must use the up and down arrow keys to move Ollie (who is hovering in mid-air on the left side of the screen) up and down and push Enter to move the part of his spacecraft that he is currently pointing at to the bottom.
 * W, G, R and C: In the fifth challenge, you must use these keys to change the colours of the empty squares on the electronic door panels to white, green, red and clear respectively; once you have completed the symmetrical patterns (which are randomly-generated), the doors will open.
 * F0: In the BBC Micro version, you can press this key in the second, ninth, eleventh and last challenges to ask for clues regarding the four space-related words in Amina and Jenny's puzzle (which are, again, randomly-generated), the planets' positions in the Solar System, Ellie's mixed-up tool names, and Ellie's misspelled words respectively; however, if you are using B-Em running in DOSBox to play this version, this key is replicated with F1 (which is also the key for a clue in the Acorn Archimedes version), and if you are using !BeebIt running in RISC OS, it is replicated by F10.

Characters

 * Ollie: An alien from the fictitious planet of Gia; in 1893, people from his planet sent a probe to Earth to check the levels of pollution, and one of them landed near the also-fictitious British town of Southbeach, in which the pollution level had become so high that the probe was in danger of exploding.
 * Amina, Martin and Jenny: The three children who Ollie meets after arriving at Southbeach in his spaceship and help him to find his people's probe.
 * Ellie: Ollie's sister, who's only mentioned in the game's text; after Ollie's communicator is mended and he calls home to Gia, she answers to say she will collect a mark three flidget (which is the part that Ollie needs to repair the probe) and leave for Earth straight away but she doesn't know the way there, so the player must guide her to the edge of the Solar System, tell her which planet is which and tell her what Earth is like before she can land.