Hammer jumps let you get a lot more height from your jumps than usual. This is a great movement tool which you combine with a lot of different movement option. To do a hammer jump, start by a horizontal attack and cancel it by a jump. Keep holding your jump and input a second horizontal slash.
Once you performed a hammer jump, you can even extend them by alternating horizontal slashes on the opposite side.
Hammer jump with Aerial Jumps
The most common and versatile way to do hammer jumps is by using an aerial jump. If you have multiple aerial jumps, you can input it again to chain them together.
Hammer jump from a Wall Jump
You can get Hammer Jumps from a wall jump. To do them, simply use hammer then wall jump and use a second hammer slash. It's important to hold the direction towards the wall before jumping.
If you have Double Jump, you can then chain another hammer jump by using your double jump right after doing one from a wall jump.
Hammer jump from a Coyote Jump
Coyote jumps are a common mechanic in platformers game which let you jump shortly after you started falling from a platform. Ori and the will of the Wisps implements that mechanic as well and it just happens that you can start a hammer jump from them. To do so walk off the platform and use an horizontal hammer slash then jump immediatly after and do another hammer slash.
If you have Double Jump, you can then chain another hammer jump by using your double jump right after doing one from a coyote jump.
Hammer jump with Glide Jump
It's also possible to perform Hammer Jumps by combining them with Glide jumps. To do so, start by doing a normal glide jump but instead of releasing glide and jumping, you want to use hammer (which will cancel your glide) then jump immediatly after and finally use a second hammer slash. It's important to hold your jump input to get the most height from a glide hammer jump. This can be done on both the standing and running variation of Glide Jumps.
If you have Double Jump, you can then chain another hammer jump by using your double jump right after doing one from a glide jump.