YS MegaBasic

YS MegaBasic is a BASIC programming language interpreter for the 1982 Sinclair Research ZX Spectrum microcomputer, written by Mike Leaman.
When loaded it left the user 22K of usable memory. YS MegaBasic allowed keywords to be spelled out letter-for-letter, which was quicker if the user had fitted a full-size full-travel keyboard to their machine, a very popular modification for serious users. This also removed the necessity for memorising the sometimes arcane key combinations necessary to enter less-commonly-used BASIC keywords. It also featured three different font sizes, user definable keys, copy-and-paste, a Sinclair QL-like windowing system, sprites and sound effects.