Exploit

In a game I recently started playing, there are tournaments that take place every ~3 days. These tournaments give great rewards that are important for progression. You'll be rewarded based on your placement. If you place really high, you'll go up a league and if you place low, you'll go down a league.

The ranking is based on how many waves you can survive. However, getting to a high wave also requires a lot of time. The tournament always runs for 24 hours and you're paired with others that started at the same time. I accidentally figured out, if you join the tournament in the last few minutes, nobody would have time to reach a high wave. Your group might also not be completely filled out. This thus makes it much easier to get large amounts of rewards.

I was in a league where I was basically going to down rank due to being severely underpowered. Now I ended up a league higher.

(There is an upgrade that increases your game speed that takes exponentially more time to research. This would obviously be a huge advantage)