Basic

Small but extremely powerful!

Contains everything you need to play all popular audio and video file formats.

Supports playback of:

    AVI, MKV, MP4, FLV, MPEG, MOV, TS, M2TS, WMV, RM, RMVB, OGM, WebM
    MP3, FLAC, M4A, AAC, OGG, 3GP, AMR, APE, MKA, Opus, Wavpack, Musepack
    DVD and Blu-ray (after decryption)
    and many more audio and video formats!

Provides lots of useful functionality, such as:

    Subtitle display
    Hardware accereration (DXVA2 / NVIDIA CUVID / Intel QuickSync)
    Audio bitstreaming
    Video thumbnails in Explorer
    File association options
    Broken codec detection
    and much more!

Same as Basic, plus:

    Media Player Classic Home Cinema (MPC-HC)
    MadVR (an advanced and high quality video renderer)
    MediaInfo Lite

This is the recommended variant for the average user.

Full
    
Same as Standard, plus:

    DC-Bass Source Mod (for OptimFrog/Tak/Tracker audio support)
    DScaler5 MPEG-2 decoder (for DVD playback in WMP on Windows XP)
    DXVA1 hardware acceleration (for Windows XP)
    ffdshow audio/video processor
    ffdshow audio/video decoder (as alternative choice for LAV decoders)
    Haali Media Splitter (as alternative choice for LAV Splitter)
    GraphStudioNext

Mega
    
Same as Full, plus:

    ACM and VFW codecs for video encoding/editing
    AC3Filter (as alternative choice for LAV and ffdshow audio decoders)
    Haali Matroska Muxer