FINALLY HERE. I am unfortunately a week late, but I'm just glad to finally finish this.
Rewatching this in editing, I realized this video might be a bit fast paced for those who don't know much about Mario Party. I tried to explain some dynamics with the grey text, but here's some extra information if you're interested.

Mario party is a turn-based game, 10 total turns. After all four players roll the dice, you all compete in a minigame for coins, which you can use to buy stars (what you need to win) or traps to steal other's coins / stars.

Specific to this game: prices of stars vary. You can also buy up to 3 stars at once. The dice also only goes up to 6, but you can get friend rolls who give you random things like extra dice.

SOURCE    • 【緊急】今から集まったメンバーでマリパやる！！！！！！！ぺこ！【ホロライブ...  
TL things: Mario's cohort or Mario's accomplice. The direct translations something like "reduced to nothing but Mario's level." Bit hard to carry that meaning across without a longer sentence in English.