Grid slots or slots of any kind with a grid as a play area have been very popular lately. Actually you can also talk about stacked reels or cascading reels, but in general there are slot machines where the symbols are falling down from above. Maybe you think of the old game Tetris where different shapes were falling down to the bottom and you should move and rotate them correctly.
Anyway, you will pretty fast notice that these slots are built in another way and can have a larger game area than traditional slots with five wheels.
As an example Reactoonz from PlayN Go have seven symbols on the height and seven reels som totally 49 symbols on the game area. Gonzos Quest is more built in a traditional way with three symbols height and five reels but is a grid slot because the symbols falls down from above and create winning patterns that then explode and get replaced by new symbols.
So, how is it to play grid slots instead of traditional slots. Well, what you notice is that more happens when the symbols explodes and get replaced, it is another way of playing a slot. The grid slots also seems to be fully packed with features and variant of wins depending on different combinations that is presented. In some slot machines of this type it is common that you have some kind of meter that should be filled and when that happens you receive a bonus or some other feature that creates extra profitable winnings.