Tecnosoft (sometimes spelt Technosoft) is a "cult" videogame company that did most of its best work on the NEC PC Engine, the MSX, and the Sega Mega Drive. They created the embryonic RTS games Herzog (1988?, MSX) and Herzog Zwei (1989, Sega Mega Drive) which were way ahead of their time. They really hit the big time with Devil Crash*, a macabre pinball sim with some shoot-'em-up elements, awesome artwork and lightning-fast gameplay.
Their flagship series was Thunder Force**. This started out as a top-down shooter, but the style quickly shifted to a side-scrolling shooter (think R-Type on steroids). Later chapters in the series pretty much sounded the death of the 2D shooter, as they were impossible to top, trouncing Konami and Irem at their own game. The final installment met with lukewarm reception in a world now firmly addicted to 3D shooters (with only Treasure still dabbling in the old skool paradigm).
In recent years, they have produced a line of cutesy looking PlayStation games (including the Neorude series, never released outside of Japan), utterly at odds with the hyperkinetic, grisly mayhem of their back catalogue. They also sell artwork and soundtrack CDs, mousemats and other collectibles, including a model of the Thunderforce V ship (which, IMHO looks a bit worse than the nifty Rynex ship from TF IV).
* Originally released on the PC Engine, later released in an enhanced form on the Sega Mega Drive (was released very belatedly as Dragon's Fury in Europe, although by this time everyone had it on import). A sequel, Dragon's Revenge, was made although probably was not handled internally. A quick perusal of the PC Engine back catalogue reveals a similar game, Alien Crush, that although not credited to Tecnosoft, could be a prequel.
**Thunder Force appeared on the MSX, I think. Thunder Force II appeared on the MSX and Mega Drive. Thunder Spirits, not created by Tecnosoft but containing elements of II & III, appeared on the SNES. Thunder Cross was a two-player coinop based on the engine of III. Thunder Force III appeared on the Sega Mega Drive. Thunder Force IV appeared on the Sega Mega Drive (as Lightening Force (sic) in the US). Thunder Force V appeared on the Sony Playstation and Sega Saturn. There were also compilations of the previous games on these formats.
Other Tecnosoft games included : Elemental Master and Hyper Duel.