To be fair, it's not exactly the same as Donkey Kong. For one, you're not trying to rescue a damsel in distress or do anything noble. You're after revenge.
|See how you like the destruction of your habitat.|
The Donkey Kong motif only really holds up for one level too. Verticality quickly becomes de-emphasized, and the fourth, final level feels more like Frogger.
When I played Zaxxon, I had some issues with its 3D collision detection, and although Congo Bongo mostly avoids Zaxxon's problem with ambiguous positions of objects relative to the terrain (although the falling coconuts can be tricky to judge), hitboxes are a bigger problem given that you have to maneuver around enemies closely and can't just shoot them from far away. It's often just not very clear where you can stand and not get killed. One time I even slid off a ledge while walking parallel to it!
I beat the loop once, but couldn't finish the first level on the second loop, and didn't feel motivated at all to try again and do better.
GAB rating: Average. Congo Bongo's biggest issue is that the stage design is a bit dull. Three of the four levels are almost completely flat, which on one hand avoids potential difficulties in wondering where the platforms and ledges exist in 3D space, but it doesn't make them very interesting to look at or play. If the levels had been more inspired, I might have felt more inclined to master its frustrating collision detection and enemy movement patterns, but alas, I didn't.
I have to wonder if Congo Bongo was popular in the UK. In a few years, sidescrolling became the de facto standard for platformers by both US and Japanese developers and stayed that way for the better part of two decades, but around the same time, axonometric platformers like Congo Bongo became a regional phenomena closely associated with the ZX Spectrum, much in the way that sidescrolling platformers became associated with the NES.