The final Bonk game on the PC-Engine brings some new gameplay elements, yet still manages to be the less enjoyable than the first two games.
Bonk can now change his size, from really big (which is just a gimmick and doesn’t add much to the gameplay, apart from the fact that you run around with a supersized Bonk) to very small (which allows you to venture into some passages that can’t be accessed in normal or supersized mode). There are even more mini-games, accessible in the levels or after beating each level.
The big step backwards is the level design, which has the same thematic problems I mentioned when speaking about the second game, but which adds some gameplay problems as well. Bonk 3 adds very big levels to the mix.
While this could have easily been a strength, it turns out exploring them isn’t much fun and more confusing than they should be (a weakness of many western computer platformer with big levels as well). In the end you wish the levels were smaller and tighter, like in the earlier Bonk games.