One of their earliest titles was QS Defenda (originally QS Defender), a clone of the Defender arcade game for the ZX80 and ZX81 home computers. Greater success followed with later releases, including a Star Raiders-style game entitled Time-Gate which reached the top of the ZX Spectrum charts in December 1982.
One of their earliest games was a clone of the Defender arcade game for the ZX80 and ZX81 home computers.  They later released a Star Raiders-style game, Time-Gate, which became popular on the ZX Spectrum.