Gobot Combiner Puzzler, Tonka/Bandai,Japan, 1980's
For me, this robot represents the end of the golden age for robot toys. Sure, it was still diecast (well, part) and it had a nice concept, but it is clearly missing the missiles and sprung laden features of Popy toys 10 years earlier...
It was one of 3 "put them together" toys of the Gobots line, a Bandai/Tonka attempt to cash into the Transformers craze of the 1980'ies. Did it succeed ? nope. (but it's a nice spinoff nevertheless.)
Lack of flexibility - parts that did not hold well together just from the start, much les after 10 hours of playtime.