I've been trying to use a SNES Game Genie with some of the games in my collection, but the results have been mixed. Some games work perfectly with the codes listed in the guidebook. However, many others do not, such as Jurassic Park and The Ignition Factor among others. This is the 2nd GG I have bought for the SNES, since my original one had the same problems. Any ideas on what may be causing it?