Makhaon Dicom Dump - is a free software
Can browse directory structure
Support analyzing, editing and viewing DICOM files
Support coloring every element of a tag - Group Number, Element Number, Length, Start At, each element of multiplicity values
Support all standard tags (under standard DICOM 2014c) and their VR (Value Representation)
Correctly parse tags with VM (Value Multiplicity)
Can add, change, delete any tag
Can add, delete sequence element
Can show and change a file preamble
Support tag designer
Support file anonymization
Can create a log while parse DICOM file
Can find some errors in the file
Can sort tags
Can search information into a file
Can expand SQ tags after load
Support hex view of file
Support store DICOM tags tree into a text file
Support save pixel data as a binary or bitmap file
Support copy pixel data to a clipboard
Support viewing loaded file or its first frame
Support display of corner overlays, orientation labels, back and bottom rulers
Can show general file info

It can, inter alia, verify different DICOM instances:

Check for Value Multiplicity (VM).
Check for unknown Value Representations (VR).
Check for VR conformity to the standard.
Check for length of the all strings.
Check for correct numbers values.
Check for character sets of strings values.
Check for UID conformity. Leading zeros and other.
Check for padding value availability and conformity to VRs.
Check for therms in the tags with help of a dictionary.
Check for same UIDs in the 0002,0002 and 0008,0016; 0002,0003 and 0008,0018.
Check for dicomdir: linked files existence, referential integrity, correct names of the files.
Some additional checks for SQ tags integrity.

Results of the check are shown in user friendly tag coloring manner.