I almost stopped playing Donkey Kong Country: Tropical Freeze altogether. What started out as a fine game came to a screeching halt in the fourth world. The terror that had been teased before suddenly became, for the most part, an entire world. What was once a minor annoyance became a source of overwhelming fury. Underwater segments. I decided to soldier on, but my overall experience had been soured. Tropical Freeze had never clicked for me in the way that Donkey Kong Country Returns did, but I still could appreciate it for what it was. The sheer volume of underwater levels crammed into one world was enough to make me question if I truly liked Tropical Freeze, or if it was really just Donkey Kong Country nostalgia still running wild.
I am a firm believer that there is no such thing as a good water level in a platformer. Water physics take the best thing about a platformer, control, and proceeds to crap all over it. The ability to control my character well and stop him or her where I want is the thing that makes platformers great, and that never translates to an underwater setting. Floaty underwater physics lends a level of realism to a game, but I'm willing to sacrifice realism in a game that stars an ape fighting Arctic mammals in Nordic attire. If given the choice between having floaty underwater physics or not, I'll take the sacrifice in realism to be able to play the game well. Something like the underwater levels from the Super Mario Bros. series is fine, but still less than satisfactory. You have more control over your character in Mario, but the added "Everything kills you now" gives a different dimension to the annoyance.
The absolute best implementation of underwater levels comes courtesy of my childhood favorite, Sonic the Hedgehog.
The Sonic series never had full blown underwater levels, but the parts in which Sonic was underwater worked well. Everything was a bit slower, and his jump seemed a bit higher, but you could still control Sonic well. Jumping on enemies still killed them, and the Spin Dash still worked as well. You could still drown, another issue I have with underwater levels, but the Sonic series treated falling into water as a punishment. As such, drowning felt appropriate. If you played a level with sprawling water sections well, you never fell in. If you messed up, you wanted to get out of the water so you could gain your momentum back to complete the level. Even though you know you had to have goofed to get there, you were empowered enough to get out quickly.
Perhaps that's my real issue. Water words, and usually even just water levels, are tiring. Limit the time stuck underwater to brief segments in which I still feel in control of the character, and they are ok. Give me an entire world of loose controls and heightened vulnerability, and I just check out.
Now don't get me started on the fact that the last world of Tropical Freeze is an ice world.