There's only one style available. If you have the extended libraries more styles are provided, or you can invest considerable time in creating your own graphics but you can cannot overcome the restriction of only one guard style for each level. This isn't Doom where imps, demons, flying skulls and numerous other creatures can all approach you simultaneously. The single guard appearance creates a repetitive game with no possibility of dramatic final confrontation scenarios between the player and some supreme enemy. The guards behaviour can be altered, so that some are intelligent and pursue you while others have an IQ that would make a conversation with a glass of water look stimulating, but more fundamental changes are needed to provide variety.
Major effort is required to generate levels that involve anything other than flat planes.
You cannot just define regions of different heights and smoothly step between them. Instead it's necessary to define each step as a platform and ensure these smoothly meet one another. It works but once generated another problem rears its ugly beta test head. Enemies appear oblivious of anything not on the same level as themselves. Useful if you want to escape from a pursuing enemy, all you need do is stand on a box in full view and they will cheerfully ignore you, but surely not an intentional effect.