Welcome to Android Central! How did you install the games--from Google Play Store, some other app store, or by downloading the apk file and manually installing? The reason I ask is that the Play Store will know if the games are compatible or not with the device, and won't let you install them if they're incompatible.
If it isn't a compatibility issue, it might be due to faulty hardware or firmware, which would not be uncommon in an off-brand device like yours.
You could try doing a factory reset, then just installing one of the games and seeing if it runs ok. If it does, then it's possible that other apps or games you installed were causing conflicts.