its really annoying that there is that next and previous games on the sides of game screen. I already pressed it twice and caused my game to change and made me reset a level.
There are a few ways to reduce/eliminate the chance to press the prev/next buttons when you don't want to.
1) Set your computer's resolution to the highest one possible if it's not already that way. This doesn't eliminate the buttons, but a lower resolution increases the chance of unintentionally pressing them.
2) Use your browser's zoom in feature (press Ctrl and - together on Chrome) to keep the prev/next buttons off the screen. This will mess up the game screen on some games, so it doesn't always work.
3) Buy AFG+ to gain full screen mode and a turn off the lights option. Either of these options will eliminate the prev/next buttons without messing up the screen, but it requires the payment of real money, which some users are unable/unwilling to.
So there are a few ways to get around the problem, but none of them are perfect.