It's a runner/gunner/metroidvania with a jetpack (technically a rocket <old gun type>) that you can use to fly around for a very limited amount of time, which is pretty fun. You can find upgrades for it to be able to fly longer, which is needed for one of the primary traversal blocks.
The worst part of the game is that all weapons except for the starting gun and the drill (a pretty powerful melee weapon doubling as another traversal block clearer) have "durability" which decreases whenever you take damage while having that weapon decreased. Once it breaks it's unusable until you collect enough energy orb drops from killed enemies to repair it, which is also the same way you regain health. Weapons can break in as few as 2 or 3 hits, depending on the weapon. Repairing them takes a LOT of these random orb drops. And checkpoints/save points save your health and ammo durability instead of replenishing them... Which all translates to much time spent farming to heal and repair.
It is probably jetpack and it is a mobile application that enables its users to play jetpack on their phones either android phones or iPhones.
is a vast field and almost everyone is using their mobile phones these days. I personally like Jetpack because it is kinda like a flappy bird but much cooler.