Tapping the PLAY menu option will take you to the main game. If you backed out of a previous game with the back arrow button on your android device, you'll be asked whether you want to continue the previous game. Just tap "YES" to continue, or "NO" to start fresh from Stage 1 with a new game.
In RGBbot, the object of the game is to neutralize all the invading evil bots in a stage. In stage 1, you'll face just one row of invaders, in stage 2, two rows, and so on. Since your defending bot has a limited range in his viewfinder, in higher stages, you'll only see about six rows of invaders at a time and the other rows will descend when you clear a row in your viewfinder range.
But how do you neutralize the invaders? You'll need to get a red, green and blue bot together either horizontally, vertically or diagonally. Just launch your defending bot up into the block of invaders with a flick of your finger or thumb on the touch screen. You can aim more precisely by using the good bot's laser guide before launching him. Just move your finger side to side until the laser points to where you want your bot to go and then flick quickly upward or along the line of the laser to launch the bot.
If you succeed in making a red-green-blue combo, the bots affected will flash white and disappear after a moment (and you as the player will get points!). Through clever play, you can arrange bots so that red-green-blue chain reactions occur -- that is, one combo disappears and as the invaders collapse inward to their tractor beam, another r-g-b combo will form and disappear.
From time to time, the neutralized evil bots will drop a "plugin device". You can have your good bot pick this up by swiping on the touch screen horizontally to move it over to the device. It will then be added to the plugin array at the top of the screen and you can have your bot select and deploy it by tapping on the device in one of the four plugin slots.
Plugin device types you may encounter are:
RedMorph, GreenMorph, BlueMorph: these allow your bot to change its color.
Colorize: after deploying, when your bot enters the invading row of evil bots, it will spread its current color to four neighboring bots.
SynapticFreeze: this will temporarily stun all of the invading bots when your bot infiltrates them. (In Timed Mode, it adds 10 seconds to the countdown timer)
Fury: after deploying, your launched bot will neutralize a complete column of invaders vertically!
Sometimes, conditions will set up a "fever" mode at the end of the stage and your good bot will have a chance to neutralize pairs of evil bots as they retreat from the planet. You can rack up big points in fever mode, so aim well!
From there just "keep on keeping on", progressing through higher more challenging stages, trying for that highest of high scores. You can always hit the android device's back button to return to the main menu and your game progress will be saved (assuming "Save game at exit" is enabled in the Settings menu option -- which is the default).
If at any time the evil bots reach your good bot on the ground (before it launches), the game will be over and the planet lost...
The font used in the game and graphics above is Ray Larabie's "Forgotten Futurist". Check his page out at http://www.larabiefonts.com.