I've played the demo and it's a nice start but I would call it a demo since it's very flawed. More like a alpha release.
Game Issues/Bugs:
-Random Enemy Placement
-Extremely unbalanced stage designs that render the game from easy (Jagged Jungle) to questionable (Scarlet Crystal Crossing) to impossible (Wrecked Rails) in the span of only 3 stages
-Barrels Sometimes don't fire and you are trapped within one (Wrecked Rails)
-Hazards are tight to pass through e.g. the Zingers in Scarlet Crystal Crossing, Buzzs in Wrecked Rails
-Timers in the Bonus Stages tend to move at MMF2's default timer making it impossible to clear some bonus stages when lag arises
-Throwing Kiddy forward with Dixie makes him roll offscreen never to be seen again until your hit or enter a barrel
-Dying sometimes in Jungle makes your death animation not activate and allows you to make small jumps but your horizontal movement is hindered
-Pausing only works with the Joypad when pausing but doesnt when out of pausing
-You get Game Over when the lives counter goes to zero rather then going from zero to nothing like in the DKC series
-I'm not completely sure but Jumping off of a vertical rope feels off, it feels like you jump too low
-You can see that i've lost a life before falling into the hole
-In Scarlet Crystal Crossing a little more than after the Checkpoint Barrel, the stage tiles become invisible until near the end of the stage
-In this picture I can skip most of the tight jumping through the Zingers by going into the Bonus Barrel, if I can just skip it, then what is the point of this part even existing for?
-I get stuck in the corner, able to change direction but not move after hitting the goal
-Kong vanishes when life lost while on the minecart
-the minecart animation is very jerky especially on steep slopes downward in which the animation doesn't stay still
-the game camera transitions clunky when entering a minecart
-The collision detection on the minecart is extremely poor, making Wrecked Rails nearly impossible if at all possible to complete
-Unlike in the DKC series, you can't always jump on any part of the rail regardless of you going up or not
-Pointless to shoot up with the cannon considering how easy it is to jump into it from the ledge. I suggest the barrel not spin so fast but instead have the Zinger spin around it since Bonus Barrels do not move.
-Dying after being shot out of a cannon in Barrel Cannon causes you to go into the first frames of the death animation but not for you to lose a life and instead you move either left or right forever
-Invisible tiles issue as in Scarlet Crystal Crossing
-Having Kritter and Kobble in the same stage is kind of pointless considering that they are essentially the same enemy
-You can infinitely roll into Krusha until you bounce high into the air
-This jump is impossible to make alone since you will die when you touch Flitter
-Sometimes when the game is minimized, the world map will vanish (possibly due to it being a video?)
-Dropping into this bonus barrel I go into the same stage with a timer as if it was a bonus stage and cant die when fall into a pit and when time runs out I start at the beginning of the stage with one life lost
-Rolljumping onto ropes causes you to go through them and stage tiles are missing in that green area
-The problem with jumping from ropes too low make it extremely difficult to make this jump and impossible for Diddy
-Surprisingly I couldn't find any technical problems with the Krizzossaurus battle as it is extremely easy aside that it gets stuck in an animation and moves right for no reason when you defeat it
-Buzzes are robotic Zingers and their appearence in Wrecked Rails doesn't make much sense since it is a Galleon/Minecart stage and not a mechanical stage
Suggestions:
-Pressing a button to select what Kong will come out of the DK Barrel
-I assume the world maps are videos files playing. If so you should turn the videos into gifs and piece the moving parts as animated sprites onto a still map to save space
-You guys should have a v-sync off version or an option in the menu to take it off because I believe that's what's causing most of the lag.
-Some bonus stage art needs to be cleaned up (Pink pixels around DK)
Personal Gripes:
-I'm not a big fan of the music, most of doesn't sound very catchy to match up with a DKC game but that's just me
-I don't understand the need to include Kiddy as he is basically Donkey Kong except he can jump on Krushas. He seems like he can be optional to have played in the game rather then to be fully incorporated in it.
Even with all of it's flaws I like the atmosphere of the crystal stages, unusual for a first level in a game. I'm not sure but maybe I can contribute concepts for level design.
AHHHHHH! EVERY DETAIL MUST BE PERFECT! AHHHHHH! 
