Here you see a picture of the "closed" cartridge: "Der flinke Architekt" (=The nimble architect)
This is how the opened cartridge looks like. To the left there's the cover, to the right the backside of the cartridge.
You can see the black plastic-"lid" and the little board
The black plastic-"lid" in the cartridge has two "sticks" which push away the closing-lid in the VCS.
In the VCS there are also two sticks which push away the closing lid in the cartridge.
The front of the board. The black piece of plastic covers the ROM.
Die "Rückseite" der Platine. Nicht besonderes.

Of course this board is sufficient for playing. You just have push away the closing-lid in the VCS with a screwdriver.