Cruel mode is a Multi-Man mode present in Super Smash Flash and Super Smash Flash 2 which originates from the Super Smash Bros. series. It challenges the player to defeat as many opponents as possible without falling from the stage, self-destructing, or being KO'd. This time, however, is a reversal of the previous Multi-Man modes with high handicaps on the player and increased aggressiveness and knockback resistance on the opponents.
In Super Smash Flash
Cruel Melee.
This mode is called Cruel Melee, as it was called in Super Smash Bros. Melee. As with other Multi-Man modes, 10-Man Melee is always played on Battlefield and the opponents are always the Fighting Shadow Team. It is the most challening of all the Multi-Man modes. Cruel Melee is actually a bit harder in SSF than in Super Smash Bros. Melee.
Because opponents get "heavier" in Cruel Melee and the reason SSF's physics already makes them a bit harder to launch them off stage with an single attack other than an up attack or a projectile, players can actually deal more than 1000% of damage to the opponents and still being unable to KO them. Additionanlly, some opponents have access to different moves that allows them to recover with ease and shoot projectiles, this considerably increases the challenge.
In Super Smash Flash 2
This mode is called Cruel Brawl, as it was called in Super Smash Bros. Brawl, in SSF's reboot, Super Smash Flash 2. It was the first mode confirmed for SSF2's Multi-Man mode thanks to a music track update in the Smash Flash DOJO!!!. As of now, there is no other source of this mode other than its music track. The opponents are yet to be revealed.The description confirms that Battlefield will be thestage for the Multi-man modes.