Fun, but also difficult. This game is very fun, but it is also very hard. There are levels of various difficulties, such as a level where you don’t have to tap, (called auto levels), all the way to levels that are pretty much impossible. There are 21 levels made by the developer, varying from an easy level, Stereo Madness, all the way to Deadlocked, a very difficult level.
However, there is more to the game than just these 21 levels. You can create your own levels using the same editor as the developer himself. If your levels are good, they can get stars, and then people will earn stars, which are pretty much a thing that you get by beating levels.
Geometry Dash can be very rage inducing, but it is also very fun. It is advised that people with epilepsy avoid the game, as there can be flashing lights, in levels, especially in a trend called nine circles levels. This trend has almost died out, but these levels can still be played.
Geometry dash is a skill based game, as you can only become good with practice. There are no ads nor in app purchases.
You will love it, and although it will probably seem very difficult at first, with a bit of practice, you will find your self having lots of fun.