Approval Processing – an automated Business Process that your organization can use to approve records in Salesforce. It specifies the:
- Steps necessary for approval -> who must approve -> the action taken.
Approval Processing Capabilities – Formula based where Salesforce formula language define the approval process rule and process step entry criteria.
Workflow Approval Retractions – submitter can recall his request anytime, Admin can control which processes can be recalled once submitted.
Approval routing uses the record owner’s hierarchy and not the approval submitter hierachy.
Jump start wizard – creates a one-step approval process
Standard Wizard – useful for complex approval processes
Parallel Approval Process – sends approval requests to multiple approves in a single step. Wait for approval from all the approves or wait for approval from any one. Configure an approval step to request approval from any combination of multiple users and related users. Max Approvers: 25
Approvals can be moved when an approver leaves the company by: assigning a new approver and making sure it has access to read the records for the approval requests.
Thys Michels Blog 
Thanks! Very helpful!