More bugs, and some thoughts regarding polish. Starting with bugs.
Menus: If you try to map a button before binding a key to another button, your first choice will stay grayed out, forcing you to exit and re-enter the menu to bind it.
Party Mode: During the end of turn screen, if multiple players are tied with no coins or stars, some of those players will be shown as 1st instead of their actual ranking.
Party Mode: When choosing who to steal from, the AI is capable of choosing a hidden option above the names that softlocks the game (Unable to reproduce. It occurred once on Wario's Battle Canyon, when a CPU player got to the ghost very early on. Maybe the AI doesn't know who to pick when everyone else is tied with less than 10 coins?).
Cavity Calamity: When playing the endless variant, if the human player is eliminated before any CPU player, all CPU players stop moving until the game ends.
Quicker Chipper: Swinging on the frame when the bar loops back to the bottom will make the ball travel the maximum distance.
Speedy Teatime: The icon showing what keys to press for direction appears over the dish cover (Note that the D-Pad icon it's supposed to hide appears under the cover).
Balloon Blast Bash: The pumps of AI players are never pressed down, even when the balloon is being pumped.
Slap Down: In the explanation screen, the text for controls overflows if keyboard controls are being shown.
Triple Jump: The icons for the face buttons are visible when playing on a keyboard.
Load, Shoot, Shield: Before the game starts, hyphens are shown in place of the countdown and action text.
Time Bomb: The AI always jumps to hit the block before the game starts.
One thing I never mentioned is that I play the game exclusively on Microsoft Edge, and I recently learned that some bugs are exclusive to certain browsers. On Firefox, keyboard remapping doesn't work at all and F2 makes the music cut out (although it slowly returns over time), and on Chrome, none of the keys are mapped to anything by default and F2 does nothing. Opera and Edge don't have these issues, but they tend to have a harder time booting up the game.
Now onto polish. The minigames Frame Perfect, Picture Match, and Stampede all have a score counter whose corners overlap the timer. While Stampede's can simply be moved to the right, and Picture Match can hide the counter until the game ends, I'm not sure what to do for Frame Perfect.
The demo videos for minigames are also in a rough state. While Token Drop, Head Waiter, and Hot Rope Jump are obvious candidates for an update, I looked through each minigame and found that all but ten [Bumper Sparks, Kabob and Weave, Speedy Teatime, Spiked Ball Scurry, Ridiculous Relay, Bomb Rally, Slap Down, Toad in the Box, Amp My Style, and T Minus Five] show outdated versions of their respective minigames, with differences ranging from slight graphical changes to old UI elements. This problem also extends to the board previews: Wiggler's Garden and Bowser's Pinball Machine are shown with their pre-0.9 layouts, Mario's Rainbow Castle and Koopa's Tycoon Town use an older design for unlucky spaces, and Yoshi's Tropical Island shows a face where a black star icon would be.
Lastly, I'm not sure why What Goes Up... and Kabob and Weave have jump commands. In the former, it goes against your objective, while in the latter, it does nothing because the ceiling is too low.