The experience you have with
Resident Evil 5: Lost in Nightmares depends entirely on what you expect out of it. If it's the shooting action you're paying for, I can't wholeheartedly recommend it. If you loved the deliberate pacing of the first three
Resident Evil games, this will be five dollars well-spent. Most of this DLC involves solving simple environmental puzzles. The entire experience is not difficult by any means, and it can be finished in an hour.
The environmental puzzles bear no explanation, but the action sequences towards the end do. The final set-piece battle of Lost in Nightmares features a rather claustrophobic environment and forces you to employ tactics not unlike the ones used in a lesser-known Capcom survival-horror game, Haunting Ground. It's a true blue survival-horror experience, but it's easy to kick the bucket when you've got almost no room to maneuver around the axe-wielding mutants.