Custom variation puzzles in the test game

please learn about the rules in this variation if you don't know before answering this quiz

Now let's go to this puzzle

Rule:

White goes first and wins a move

Difficulty: 1490

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[StartFen4 "R-0,1,0,1-1,1,1,1-1,1,1,1-0,0,0,0-0-{'seirawanDrops':(('k9','h4'),(),('h11','j9'),(),()),'pawnBaseRank':5,'wb':true,'dim':'8x8','bank':('rR','','','')}-x,x,x,x,x,x,x,x,x,x,x,x,x,x/x,x,x,x,x,x,x,x,x,x,x,x,x,x/x,x,x,x,x,x,x,x,x,x,x,x,x,x/x,x,x,4,yK,3,x,x,x/x,x,x,8,x,x,x/x,x,x,6,yW,rI,x,x,x/x,x,x,8,x,x,x/x,x,x,8,x,x,x/x,x,x,8,x,x,x/x,x,x,8,x,x,x/x,x,x,4,rK,3,x,x,x/x,x,x,x,x,x,x,x,x,x,x,x,x,x/x,x,x,x,x,x,x,x,x,x,x,x,x,x/x,x,x,x,x,x,x,x,x,x,x,x,x,x"]
[Variant "FFA"]
[RuleVariants "EnPassant ForcedCapture Play4Mate SeirawanSetup"]
[CurrentMove "0"]
[TimeControl "10 | 15"]

"Difficulty: 1650" ???

This is much easier

Kd1/@Re1#

Kd2/@Re1#

Kf1/@Re1#

Kf2/@Re1#

so let me fix it to 1490

but one of the two rules already...