Working in concert with a modified version of C64 Emulator Frodo, Mathfigure's hacking tool ICU64 allows you to zoom up to and monitor bits of memory in use, view and edit game sprites and stages, and conduct other experiments.

The above video of Boulder Dash 4 demonstrates how the utility can grab and display the entire stage from the game's memory, instead of showing just a portion as originally designed.

True Chip Till Death explains ICU64's significance: "Many of these features have been long available through a freezing cart, but they never have been represented graphically, and, here’s the catch: you don’t need to freeze the computer, you can affect the memory map, realtime, in a variety of ways."

You can watch another video of ICU64 hacking below and read more about the under development tool here.