The Gemini controllers were a true work of design genius! They opted for the least amount of internal parts to have to replace. The paddles were (from what I've read) meant to work with a Y connecter, but will usually work with paddle games without it. Kaboom will start with a toggle of the top stick, whereas Jedi Arena will not work. All Atari sticks and paddles will work (on the Gemini), though, BUT, will all games work? I have problems with Keystone Kapers, for instance! The enemy will disappear and reappear and the screen will flicker occasionally!! All other games that I've played work great and have excellent color and clarity! Back to the controllers, though..
The stick and paddles contact the same pcb that has no chips, resistors, capacitors or the like (same as Atari sticks)! However, there are no pots for the paddle! It slides along a circular contact ring with stoppers!! There is a metal tension rod for the button and everything works with these little feather-like brush feelers that touch the pcb!! You may get a bit of a workout with the button, but I found that playing left or right handed works equally well (although I switch wires on my 2600 sticks to have the button on the right on some, and make my own arcade joysticks for use on Atari etc. as nothing beats a true arcade joystick and buttons for these games!!)!! These controllers have very few parts and a quick cleaning of the paddle ring can bring them back to perfection, unlike the greasy mess that is the atari paddle fix. A stick, a wheel, a button, a board, some six metal 'feelers', screws, and a top and bottom housing! Thats IT!! I really love how smoothly the stick controls, and beats the harder, cheaper versions of the atari sticks hands down!!