The Game Genie is a mini cartridge that attaches to a game cart (to apply cheats/mods through a code-entry screen). This combo is then inserted into the NES, Game Genie-first. The combo is too long to be pushed down, and the NES door remains open while playing.
I never understood why you don't need to push "down" the Game Genie; a bare cart would never function unless pushed down...
Nevertheless, every game I had that would not work in the NES would work just fine with the Game Genie attached (and you can always choose to enter zero cheat codes). The Game Genie seemed to make everything a bit tighter. When inserted into the NES, there isn't much wiggle room, if I recall.
edit: Wikipedia says, "Therefore, the Game Genie was designed in such a way that it did not need to be depressed in order to start the game. This design put even more stress on the ZIF socket than standard game insertion, bending pins and eventually causing units to be unplayable without the Game Genie present." https://en.wikipedia.org/wiki/Game_Genie
you didn't need to push down on the game genie, because the "push down" was to enable the CIC lockout chip. Galoob spent a considerable amount of time (and legal fees) bypassing the CIC chip. this allowed all games to run without problems on most NES systems.
I never understood why you don't need to push "down" the Game Genie; a bare cart would never function unless pushed down...
Nevertheless, every game I had that would not work in the NES would work just fine with the Game Genie attached (and you can always choose to enter zero cheat codes). The Game Genie seemed to make everything a bit tighter. When inserted into the NES, there isn't much wiggle room, if I recall.
edit: Wikipedia says, "Therefore, the Game Genie was designed in such a way that it did not need to be depressed in order to start the game. This design put even more stress on the ZIF socket than standard game insertion, bending pins and eventually causing units to be unplayable without the Game Genie present." https://en.wikipedia.org/wiki/Game_Genie