Here is a short summary of the main features of Dream64 :

• Cycle (almost) exact commodore 64 CPU's emulation (PAL)
• Cycle exact VIC emulation, all graphic modes, sprites etc. (PAL)
• SID Emulation (filters are not implemented)
• One 1541 Drive (CPU emulated)
• Joystick emulation (you can "plug" one joystick on port 1 or 2 of the C64), use the numeric Pad or a real PC GamePad.
• Direct3D display with bilinear filtering and fullscreen mode (ALT+Enter)
• Auto load function (tries to load a disk or tape image automatically )
• A very primitive debugger for C64 CPU and 1541 CPU
• PRG P00 D64 T64 file support

Some of the missing features :

• A perfect timing...
• Complete IRQ handling
• Emulation of more than one 1541 drive
• Emulation of 2 joysticks at a time
• Mouse emulation
• NTSC timing
• SID filters for better sound
• A GUI for replacing menus
• Command line arguments to launch games on a double-click
• A configuration panel (to enable  / disable sound, set display size and so on)
• Save state feature
• Cartridge image support
• And a lot more.....