Returns and Tropical Freeze are really great, mechanically, but Rare's series was much clearer in its post-cold war message.
At the beginning of DKC1, the Kongs were greedy capitalists, interested in political rule only insofar as it allowed them to hoard bananas.
The Kremlin(gs) displaced the regime in order to redistribute wealth. Their means were drastic -- all dissenters were shoved into barrels and crates -- but the rest of the population came to be on their side, and received a reasonable stipend in exchange for military service.
The Kongs were the only animals who wanted more than they needed, and managed to reclaim their wealth by regaining power. They came to value power as much as they valued the wealth it represented.
In DKC2, the Kongs become imperialist, conquering the Kremlings' own territory. K. Rool's shift from a political leader to a military captain shows a shift in focus. This game is the darkest of the bunch, and shows a world with currency, but still in ruin. The ships have all crashed, the lava has erupted, the amusement park has gaps in its roller coaster tracks. Perhaps this shows the reality of a failed empire that had idealistic ambitions. The fun zone is taken over by briars and bees.
DKC3's K. Rool became a scientist, which seems representative of the space race, culminating in the DKC's last level, where the Kongs commandeer a rickety rocket and after that, an elegant bird. Baron K. Roolenstein's robot was made of impressive technology, but was ultimately a novelty made of what was lying around, easily dispatched by stupid, brutish force. America.
Retro's series maintains the Kongs' greed, but I don't know what the Tikis are doing. Do drums want bananas or power or anything at all? There is one scene in Tropical Freeze where a parliament of owls destroys a banana with a sledgehammer, which seems like it could be something more than a Gallagher reference, but I don't know.