Some tips:
- Aim for their heads or torsos. The hammer is more effective if it makes a solid, full contact rather than a just-in-range touch.
- Sometimes the overhead swing is better at insta-killing the target, but more precision is required.
- The jetpack can be used to lunge forward in explosive bursts timed to your swings.
- Be careful to swing in a direction that doesn't hit walls
- Upgrade your hammer! It gets a lot easier to hit things the bigger it is.
- Your hammer brings the most advantage against targets that are good at blocking swords. (Mark 2-4 swordsmen for example)
- The sword is probably a more efficient choice for quickly dispatching archers in tight spaces.
Hope that helps! :)