diff --git a/parts/player/gameEnv0.lua b/parts/player/gameEnv0.lua
index 5ecace2cf..4e03416d7 100644
--- a/parts/player/gameEnv0.lua
+++ b/parts/player/gameEnv0.lua
@@ -65,11 +65,11 @@ return {
 
     -- Some Events are registered in player/init.lua, see "tableNeedMerge"
     extraEvent={
-        {'attack',4},
+        {'attack',5},
     },
     extraEventHandler={
-        attack=function(P,P2,...)
-            P:beAttacked(P2,...)
+        attack=function(P,source,...)
+            P:beAttacked(source,...)
         end,
     },
 
diff --git a/parts/player/init.lua b/parts/player/init.lua
index cafd04ec2..3df3eda4b 100644
--- a/parts/player/init.lua
+++ b/parts/player/init.lua
@@ -250,9 +250,9 @@ local tableNeedMerge={
     'hook_spawn',
     'hook_hold',
     'hook_die',
-    'extraEvent',
+    'hook_atk_calculation',
+    'task',
 }
-for _,k in next,tableNeedMerge do gameEnv0[k]={} end
 local function _mergeFuncTable(f,L)
     if type(f)=='function' then
         ins(L,f)
@@ -266,16 +266,14 @@ end
 local function _applyGameEnv(P)-- Finish gameEnv processing
     local ENV=P.gameEnv
 
-    -- Create event tables
+    -- Apply events
     for i=1,#tableNeedMerge do
         ENV[tableNeedMerge[i]]=_mergeFuncTable(ENV[tableNeedMerge[i]],{})
     end
 
     -- Apply eventSet
-    while true do
-        if not (ENV.eventSet and ENV.eventSet~="X") then
-            break
-        end
+    repeat
+        if not (ENV.eventSet and ENV.eventSet~="X") then break end
         if type(ENV.eventSet)~='string' then
             MES.new('warn',"Wrong event set type: "..type(ENV.eventSet))
             break
@@ -286,7 +284,11 @@ local function _applyGameEnv(P)-- Finish gameEnv processing
             break
         end
         for k,v in next,eventSet do
-            if k=='extraEventHandler' then
+            if k=='extraEvent' then
+                for _,ev in ipairs(v) do
+                    table.insert(ENV.extraEvent, ev)
+                end
+            elseif k=='extraEventHandler' then
                 for ev,handler in next,v do
                     if ENV.extraEventHandler[ev] then
                         local prevHandler=ENV.extraEventHandler[ev]
@@ -306,8 +308,7 @@ local function _applyGameEnv(P)-- Finish gameEnv processing
                 ENV[k]=v
             end
         end
-        break
-    end
+    until true
 
     P._20G=ENV.drop==0
     P.dropDelay=ENV.drop
diff --git a/parts/player/player.lua b/parts/player/player.lua
index aa58531af..02d18d0c4 100644
--- a/parts/player/player.lua
+++ b/parts/player/player.lua
@@ -909,12 +909,45 @@ function Player:ifoverlap(bk,x,y)
     end
 end
 function Player:attack(R,send,time,line)
-    self:extraEvent('attack',R.sid,send,time,line)
-end
-function Player:beAttacked(P2,sid,send,time,line)
-    if self==P2 or self.sid~=sid then return end
-    self:receive(P2,send,time,line)
-    P2:createBeam(self,send)
+    local sid=R.sid
+    -- Add the attack to the list of in-transit attacks.
+    -- These attacks will be able to cancel with incoming attacks that cross them.
+    if not self.inTransitAttacks then
+        self.inTransitAttacks={}
+    end
+    if not self.inTransitAttacks[sid] then
+        self.inTransitAttacks[sid]={seenAttacks=0}
+    end
+    table.insert(self.inTransitAttacks[sid], {send=send, time=time, line=line})
+    -- Send the attack
+    -- We also send the number of seen attacks from this player.
+    -- This allows that player to know which attacks are still in transit, and which have already arrived.
+    -- This is because... if a player already saw an attack before sending this one, the attacks did not cross.
+    -- But if they didn't see the attack, then the attacks must have crossed (and should cancel each other)
+    self:extraEvent('attack',sid,send,time,line,self.inTransitAttacks[sid].seenAttacks)
+end
+function Player:beAttacked(source,target_sid,send,time,line,seenCount)
+    -- Only recieve the attack if you are the target.
+    if self==source or self.sid~=target_sid then return end
+
+    if not self.inTransitAttacks then
+        self.inTransitAttacks={}
+    end
+    if not self.inTransitAttacks[source.sid] then
+        self.inTransitAttacks[source.sid]={seenAttacks=0}
+    end
+    -- Increment the number of seen attacks from that player.
+    self.inTransitAttacks[source.sid].seenAttacks=self.inTransitAttacks[source.sid].seenAttacks + 1
+    -- Block against any in-transit attacks before recieving (this prevents passhtrough)
+    for i=seenCount+1,#self.inTransitAttacks[source.sid] do
+        local atk=self.inTransitAttacks[source.sid][i]
+        local cancel=MATH.min(atk.send, send)
+        atk.send=atk.send-cancel
+        send=send-cancel
+    end
+
+    self:receive(source,send,time,line)
+    source:createBeam(self,send)
 end
 function Player:receive(A,send,time,line)
     self.lastRecv=A
diff --git a/version.lua b/version.lua
index 5dca7c19d..a3be5749b 100644
--- a/version.lua
+++ b/version.lua
@@ -2,6 +2,6 @@ return {
     ["apkCode"]=1722,
     ["code"]=1722,
     ["string"]="V0.17.22",
-    ["room"]="ver A-14",
+    ["room"]="ver A-15",
     ["name"]="暂停 Break",
 }