This is the Dunk-Z Robot made in Korea. Its a combination of a Machine Robo Power Suit and super robots.
The large robot forms similar to the Power Suits. It can also form several vehicles, and the smaller super robot figures stay attached via magnets on the feet.
The Power Suit is a copy of the Machine Robo Land Commander 5 set (seen below), which was planned to be part of the Gobots line as Nemesis, but was never actually incorporated.
Here's a close-up o fthe super robots that come with the set. These are nice chrome figures, including Great Mazinger, Tetsujin 28, Acrobunch, and Godsigma.
These are the instructions for the set. They show many combinations that can be formed by use of this and another apparent toy in the series that was designed similar to the Gobots Courageous or Grungy Power Suit.
The toy even comes with a small model kit to form a robot. The kit is of nice quality, coming with a transparent dome, screws, glue, and decals (not visible in the photo). It seems that there are four different possible models that could come with this set or perhaps other sets in the series.