Stupid Invaders/Gameplay

Controls

 * Mouse: In the Windows and Mac OS versions of the game, you must use your computer's mouse to direct the cursor around the screen; however, in the Dreamcast version, you must use either the analog thumb pad or D-Pad instead. The cursor automatically changes its appearance depending on what you select on-screen and what the alien you are currently controlling can do - and in the Windows and Mac OS versions, you shall have to click on the mouse's left button to walk in a given direction (indicated by a hand pointing), look at something (indicated by a hand holding an eyeball), take something (indicated by a hand with outstretched fingers), use an object (indicated by a hand holding a joystick) and talk to someone (indicated by a side-viewed hand with outstretched fingers), but in the Dreamcast version, you shall have to press A instead. Once your alien takes something, the cursor will take the appearance of the item, and you can then place it in the inventory by clicking the mouse's right button; in the Dreamcast version, you will have to press B instead. Your alien can carry up to six items - and they can be used on the background objects as well as with each other.
 * Space: In the Windows and Mac OS versions, you must push this key to bring up the inventory, but in the Dreamcast version, you must press X or Y instead; to use an item, first select it by clicking on it, then either click on a background object or drag it over to a second item in the inventory.
 * F2: In the Windows and Mac OS versions, you must press this key to save your progress, but in the Dreamcast version, you must press Start and select "Save Game" instead; if all nine spaces are full, you can display more by clicking the feet on either side of the screen. You can save up to 27 games, and you can also save over an already-existing game - however, your previously saved game in that space shall be erased as a result of it.
 * F1: In the Windows and Mac OS versions, you must push this key to load a saved game, but in the Dreamcast version, you must press Start and select "Load Game" instead; once you've clicked on the space of the game you want to load, you will have to confirm your choice by clicking "Yes".
 * F3: In the Windows and Mac OS versions, you'll have to push this key to change the volume, subtitles and colour settings, but in the Dreamcast version, you must push Start and select "Settings" instead; the Dreamcast version also has a "mono/stereo" sound setting instead of a "colour" one.
 * Esc: In the Windows and Mac OS versions, you must push this key to quit, then confirm your choice by clicking "Yes"; in the Dreamcast version, you must press Start, select "Quit" and select "Yes" instead (doing this on the main menu also returns you to Windows, Mac OS, or the title screen).