Flappy was a 1983 sokoban-like puzzle game released by db-Soft for the Sharp X1 computer. It was quickly ported to other Japanese computers, and eventually made its way to the Nintendo Famicom by 1985, but is relatively unknown beyond Japan.
Each level also contains enemies, some of which will hunt you, others will simply patrol an area of the screen. They can be crushed by boulders, and Flappy can pick up what looks like mushrooms to chuck at them to temporarily stun them to make this easier.
That said, if you do like puzzle games of the "push stuff around" sokoban-style variety, Flappy isn't offensively bad... just a bit lacking in variety despite the 200 stages the game offers. I give Flappy a C rating.