Working Designs made a bunch of great games for the TurboGrafx-16...well, mostly the Turbo CD and Super CD/Turbo Duo. And for a while, a TurboGrafx based system was the only way to play them. Later they would be available on systems like the Saturn and PlayStation but not in 1993 when Vasteel was released (though they did have a couple of releases for the Sega CD also).
Vasteel was actually first released for the PC Engine in Japan in 1990. It was localized for the North American market and released for the TurboGrafx-16 (Turbo CD) by Working Designs relatively late in the life of the system in 1993. Vasteel is a hybrid strategy action game. Much of the game plays like a hex based strategy game but when enemy units meet the combat is real-time action. There is a single-player story line to follow that involves a civil war on the governing planet of the Vasteel solar system. You can also simply play against another player.
Hard-core strategy enthusiasts might not like this game because of the action sequences and those who like only action games are not going to like the strategy portions. However, if you like both types of games then this game is definitely worth a try. Reviews were mixed but I think it was a pretty decent game.
As far as I know, Vasteel was exclusive to the TurboGrafx-16 so if you want to try it you will have to track down an original copy (and Working Designs games tend to be expensive) or make do with emulation. There was a sequel, also for the Turbo CD, that was released in 1994. However, it was only available in Japan. This was a pure strategy game and got rid of the action sequences.