Barrage Populaire

You probably cannot. It's a simulation of voting. The "rainbow-like structure" is a representation of the French National Assembly. When you click, you're overturning a seat against le RN (english: the National Rally), an extreme right wing political party. Overtime, as you flip seats, some of them will be overturned back to le RN. The timer represents the time for voting. So, it is possible to claim enough seats to prevent Marine le Pen from taking over,

The reason people are worried is that at the EU Elections, a coalition of far right parties won a 31% plurality (the largest section of votes, but thankfully not a literal majority). So, the assumption is that more voters that are generally expected to vote will vote for the far right parties in the French General Election (as the largest portion who showed up for the EU Elections voted for far right parties/coalitions). This game is to encourage you to vote in the election and make your vote for certain values and against certain others (as demonstrated by the slogans proclaimed by the people voting at the bottom whose votes are produced by your clicking).

It is encouraging people who believe in the values professed by the people passing by at the bottom to go out and vote to "deal a blow" against the fascists and take a stand for their own values as well as well as to not get complacent, because if you slow down because you're winning, the fascists will pick up pace behind you.