diff --git a/Zenitha b/Zenitha
index cb6ee932..ce3a78b5 160000
--- a/Zenitha
+++ b/Zenitha
@@ -1 +1 @@
-Subproject commit cb6ee932a5a139f490fcaa6ae8b50b8d883f28e5
+Subproject commit ce3a78b51661399296c562441b4a1096b383ed17
diff --git a/assets/game/acryPlayer.lua b/assets/game/acryPlayer.lua
index 94faeabc..2013f47c 100644
--- a/assets/game/acryPlayer.lua
+++ b/assets/game/acryPlayer.lua
@@ -783,11 +783,11 @@ end
 -- Other
 
 function AP:decodeScript(line,errMsg)
-    -- TODO
+    -- TODO (script)
     -- error(errMsg.."No string command '"..cmd.."'")
 end
 function AP:checkScriptSyntax(cmd,arg,errMsg)
-    -- TODO
+    -- TODO (script)
 end
 
 --------------------------------------------------------------
diff --git a/assets/game/brikPlayer.lua b/assets/game/brikPlayer.lua
index 11d57be9..f68b5c49 100644
--- a/assets/game/brikPlayer.lua
+++ b/assets/game/brikPlayer.lua
@@ -1902,7 +1902,7 @@ function BP:decodeScript(line,errMsg)
 end
 function BP:checkScriptSyntax(cmd,arg,errMsg)
     if cmd=='setField' then
-        -- TODO
+        -- TODO (script)
     elseif cmd=='switchAction' then
         assert(self._actions[arg],"Invalid action name '"..arg.."'")
     elseif cmd=='clearHold' then
@@ -1911,7 +1911,7 @@ function BP:checkScriptSyntax(cmd,arg,errMsg)
         assert(arg==nil,errMsg.."No arg needed")
     elseif cmd=='pushNext' then
         if type(arg)=='string' then
-            -- TODO
+            -- TODO (script)
         elseif type(arg)=='table' then
             for i=1,#arg do
                 assert(Brik.get(arg[i]),errMsg.."Invalid brik id '"..arg[i].."'")
diff --git a/assets/game/brikmap.lua b/assets/game/brikmap.lua
index 3304997b..288eac41 100644
--- a/assets/game/brikmap.lua
+++ b/assets/game/brikmap.lua
@@ -17,9 +17,8 @@ local tau=MATH.tau
 --  Z
 local modes={
     {pos={10,10,0},name='marathon'},
-    {pos={10,25,0},name='techrash_easy'},
     {pos={25,25,0},name='hypersonic_lo'},
-    {pos={25,35,0},name='techrash_hard'},
+    {pos={25,35,0},name='techrash'},
     {pos={35,35,0},name='hypersonic_hi'},
     {pos={55,55,0},name='hypersonic_ti'},
     {pos={35,45,0},name='hypersonic_hd'},
@@ -83,9 +82,8 @@ local modes_str={} for i=1,#modes do modes_str[modes[i].name]=modes[i] end
 
 local bridgeLinks={
     'marathon - dig_practice - sprint_40 - marathon',
-    'marathon - techrash_easy',
     'marathon - hypersonic_lo - hypersonic_hi - hypersonic_ti',
-    'hypersonic_lo - techrash_hard',
+    'hypersonic_lo - techrash',
     'hypersonic_hi - hypersonic_hd',
     'marathon - combo_practice - ac_easy - ac_hard - ac_challenge',
     'combo_practice - tsd_practice - tsd_easy - tsd_hard',
diff --git a/assets/game/gelaPlayer.lua b/assets/game/gelaPlayer.lua
index 06c7cf98..e85262e5 100644
--- a/assets/game/gelaPlayer.lua
+++ b/assets/game/gelaPlayer.lua
@@ -1384,11 +1384,11 @@ end
 -- Other
 
 function GP:decodeScript(line,errMsg)
-    -- TODO
+    -- TODO (script)
     -- error(errMsg.."No string command '"..cmd.."'")
 end
 function GP:checkScriptSyntax(cmd,arg,errMsg)
-    -- TODO
+    -- TODO (script)
 end
 
 --------------------------------------------------------------
diff --git a/assets/game/mechanicLib/brik/misc.lua b/assets/game/mechanicLib/brik/misc.lua
index 3a17f640..5acffe7c 100644
--- a/assets/game/mechanicLib/brik/misc.lua
+++ b/assets/game/mechanicLib/brik/misc.lua
@@ -326,7 +326,7 @@ do -- obstacle
     end)
 end
 
-do -- Cascade
+do -- cascade
     local function getSolidMat(P)
         local F=P.field
         local visitedMat={}
diff --git a/assets/game/mechanicLib/brik/music.lua b/assets/game/mechanicLib/brik/music.lua
index c7d294c7..006009d3 100644
--- a/assets/game/mechanicLib/brik/music.lua
+++ b/assets/game/mechanicLib/brik/music.lua
@@ -122,17 +122,12 @@ function music.marathon_afterClear(P)
     FMOD.music.setParam('level_marathon_exterior',(md.level or 1)+(md.ascend or 0))
 end
 
-function music.techrash_easy_afterClear(P)
-    if not P.isMain then return true end
-    FMOD.music.setParam('intensity',MATH.icLerp(4,10,P.modeData.techrash))
-end
-
 function music.hypersonic_lo_afterSpawn(P)
     if not P.isMain then return true end
     FMOD.music.setParam('intensity',MATH.icLerp(100,300,P.modeData.point))
 end
 
-function music.techrash_hard_afterClear(P)
+function music.techrash_afterClear(P)
     if not P.isMain then return true end
     FMOD.music.setParam('intensity',MATH.icLerp(4,10,P.modeData.techrash))
 end
diff --git a/assets/game/mechanicLib/brik/progress.lua b/assets/game/mechanicLib/brik/progress.lua
index c9db5af2..531cec96 100644
--- a/assets/game/mechanicLib/brik/progress.lua
+++ b/assets/game/mechanicLib/brik/progress.lua
@@ -256,12 +256,6 @@ do -- sprint_dizzy_40
 end
 
 do -- marathon
-    function progress.marathon_afterClear(P)
-        if not P.isMain then return true end
-        if P.modeData.stat.clears[4]==16 then
-            PROGRESS.setModeState('brik_stdMap','techrash_easy')
-        end
-    end
     function progress.marathon_gameOver(P,reason)
         if not P.isMain then return true end
         if reason=='AC' then
@@ -270,20 +264,11 @@ do -- marathon
     end
 end
 
-do -- techrash_easy
-    function progress.techrash_easy_afterClear(P)
-        if not P.isMain then return true end
-        if P.modeData.stat.clears[4]>=20 then
-            PROGRESS.setModeState('brik_stdMap','techrash_easy',1)
-        end
-    end
-end
-
 do -- hypersonic_lo
     function progress.hypersonic_lo_afterClear(P)
         if not P.isMain then return true end
         if P.modeData.stat.clears[4]==36 then
-            PROGRESS.setModeState('brik_stdMap','techrash_hard')
+            PROGRESS.setModeState('brik_stdMap','techrash')
         end
     end
     function progress.hypersonic_lo_gameOver(P,reason)
@@ -295,11 +280,11 @@ do -- hypersonic_lo
     end
 end
 
-do -- techrash_hard
-    function progress.techrash_hard_afterClear(P)
+do -- techrash
+    function progress.techrash_afterClear(P)
         if not P.isMain then return true end
         if P.modeData.stat.clears[4]>=20 then
-            PROGRESS.setModeState('brik_stdMap','techrash_easy',1)
+            PROGRESS.setModeState('brik_stdMap','techrash',1)
         end
     end
 end
diff --git a/assets/game/mechanicLib/brik/sequence.lua b/assets/game/mechanicLib/brik/sequence.lua
index 8225210c..50ba8db9 100644
--- a/assets/game/mechanicLib/brik/sequence.lua
+++ b/assets/game/mechanicLib/brik/sequence.lua
@@ -37,7 +37,7 @@ function sequence.bag7(P,d,init)
     return rem(d.bag,P:random(#d.bag))
 end
 
-function sequence.bag7_p1fromBag7(P,d,init) -- bag8, which the extra piece from another bag
+function sequence.bag7_p1fromBag7(P,d,init) -- bag7 + 1 from another bag7
     if init then
         d.bag={}
         d.extra={}
@@ -125,7 +125,7 @@ function sequence.bag7_sprint(P,d,init) -- bag7, but no early S/Z/O and shufflin
     end
 end
 
-function sequence.bag7_spreadFirstTo3211(P,d,init) -- bag7, but first bag 3+2+1+1-ly splited into next four bags 
+function sequence.bag7_spread1stTo3211(P,d,init) -- bag7, but first bag 3+2+1+1-ly splited into next four bags 
     if init then
         d.bag={}
         d.victim=TABLE.copy(Tetros)
diff --git a/assets/game/mechanicLib/brik/techrashChallenge.lua b/assets/game/mechanicLib/brik/techrashChallenge.lua
index d0d23b91..57cb272c 100644
--- a/assets/game/mechanicLib/brik/techrashChallenge.lua
+++ b/assets/game/mechanicLib/brik/techrashChallenge.lua
@@ -1,84 +1,6 @@
-local gc=love.graphics
-
 ---@type Map<Techmino.Mech.Brik>
 local techrash={}
 
-function techrash.easy_seqType(P,d,init)
-    if init then
-        P.modeData.bagLoop=0
-        d.l1={}
-        d.l2={}
-        return
-    end
-    -- Fill list1 (bag7_p0to4_by_bagLoop_fromBag6_noI)
-    if not d.l1[1] then
-        P.modeData.bagLoop=P.modeData.bagLoop+1
-        for i=1,7 do table.insert(d.l1,i) end
-        for _=1,
-            P.modeData.bagLoop<=10 and 0 or
-            P.modeData.bagLoop<=20 and 1 or
-            P.modeData.bagLoop<=30 and 2 or
-            P.modeData.bagLoop<=40 and 3 or
-            4
-        do
-            -- Fill list2 (bag6_noI)
-            if not d.l2[1] then for i=1,6 do table.insert(d.l2,i) end end
-            table.insert(d.l1,table.remove(d.l2,P:random(#d.l2)))
-        end
-    end
-    return table.remove(d.l1,P:random(#d.l1))
-end
-function techrash.easy_event_playerInit(P)
-    P.modeData.techrash=0
-    P.modeData.minH=0
-end
-function techrash.easy_event_afterLock(P)
-    local minH=P.field:getHeight()
-    for x=1,P.settings.fieldW do
-        for y=P.field:getHeight(),0,-1 do
-            if P.field:getCell(x,y) then
-                if y<minH then minH=y end
-                break
-            end
-        end
-    end
-    P.modeData.minH=minH
-end
-function techrash.easy_event_afterClear(P,clear)
-    P:triggerEvent('afterLock') -- Force refresh
-    if P.hand.name=='I' and clear.line>=4 then
-        P.modeData.techrash=P.modeData.techrash+1
-        if P.modeData.techrash>1 then
-            P:playSound('charge',math.min(math.floor((P.modeData.techrash+2.6)^1.2/5.4),11))
-        end
-        local HC=P.field:getHeight()==0
-        if not HC then
-            HC=true
-            for x=1,P.settings.fieldW do
-                if #P:getConnectedCells(x,1)%4~=0 then
-                    HC=false
-                    break
-                end
-            end
-        end
-        if HC then P:playSound('frenzy') end
-        P.modeData.bagLoop=math.max(P.modeData.bagLoop-(P.lastMovement.combo-1)*2-(HC and 2 or 0),0)
-    else
-        P:finish('PE')
-    end
-end
-function techrash.easy_event_drawInField(P)
-    gc.setColor(1,1,1,.26)
-    for y=P.modeData.minH+4,19,4 do
-        gc.rectangle('fill',0,-y*40-2,P.settings.fieldW*40,4)
-    end
-end
-function techrash.easy_event_drawOnPlayer(P)
-    P:drawInfoPanel(-380,-60,160,120)
-    FONT.set(80) GC.mStr(P.modeData.techrash,-300,-70)
-    FONT.set(30) GC.mStr(Text.target_techrash,-300,15)
-end
-
 local initPower=3
 local initSidePower=0
 local maxPower=6
@@ -90,13 +12,13 @@ local infoMeta={__index=function(self,k)
     self[k]={charge=0,_charge=0}
     return self[k]
 end}
-function techrash.hard_event_playerInit(P)
+function techrash.event_playerInit(P)
     P.modeData.techrash=0
     P.modeData.chargePower=initPower
     P.modeData.sidePower=initSidePower
     P.modeData.techrashInfo=setmetatable({},infoMeta)
 end
-function techrash.hard_event_always(P)
+function techrash.event_always(P)
     for _,v in next,P.modeData.techrashInfo do
         if v._charge~=v.charge then
             if v._charge<v.charge then
@@ -110,7 +32,7 @@ function techrash.hard_event_always(P)
         end
     end
 end
-function techrash.hard_event_afterClear(P,clear)
+function techrash.event_afterClear(P,clear)
     if P.hand.name=='I' and clear.line==4 then
         local list=P.modeData.techrashInfo
         local x=P.handX
@@ -145,7 +67,7 @@ function techrash.hard_event_afterClear(P,clear)
         P:finish('PE')
     end
 end
-function techrash.hard_event_drawBelowMarks(P)
+function techrash.event_drawBelowMarks(P)
     local t=love.timer.getTime()
     for k,v in next,P.modeData.techrashInfo do
         if v._charge>0 or v.dead then
@@ -174,6 +96,10 @@ function techrash.hard_event_drawBelowMarks(P)
         end
     end
 end
-techrash.hard_event_drawOnPlayer=techrash.easy_event_drawOnPlayer
+function techrash.event_drawOnPlayer(P)
+    P:drawInfoPanel(-380,-60,160,120)
+    FONT.set(80) GC.mStr(P.modeData.techrash,-300,-70)
+    FONT.set(30) GC.mStr(Text.target_techrash,-300,15)
+end
 
 return techrash
diff --git a/assets/game/mechanicLib/gela/colorSet.lua b/assets/game/mechanicLib/gela/colorSet.lua
index 6fdb07b9..6f716b94 100644
--- a/assets/game/mechanicLib/gela/colorSet.lua
+++ b/assets/game/mechanicLib/gela/colorSet.lua
@@ -10,7 +10,7 @@ colorSet.dark   ={400,440,014,141,204,144,420,413}
 colorSet.greyscale={111,333,777,999,888,555,444,222}
 
 function colorSet.getRandom(P)
-    -- TODO
+    -- TODO: reasonable random color
 end
 
 return colorSet
diff --git a/assets/game/mechanicLib/gela/sequence.lua b/assets/game/mechanicLib/gela/sequence.lua
index 6c2921f2..07f483f2 100644
--- a/assets/game/mechanicLib/gela/sequence.lua
+++ b/assets/game/mechanicLib/gela/sequence.lua
@@ -60,6 +60,6 @@ end end
 --------------------------------------------------------------
 -- Multi
 
--- TODO
+-- TODO: complicate shade puyo sets
 
 return sequence
diff --git a/assets/game/mode/brik/exterior/marathon.lua b/assets/game/mode/brik/exterior/marathon.lua
index 705035da..d26c3775 100644
--- a/assets/game/mode/brik/exterior/marathon.lua
+++ b/assets/game/mode/brik/exterior/marathon.lua
@@ -15,7 +15,6 @@ return {
             },
             afterClear={
                 mechLib.brik.music.marathon_afterClear,
-                mechLib.brik.progress.marathon_afterClear,
             },
             gameOver=mechLib.brik.progress.marathon_gameOver,
         },
diff --git a/assets/game/mode/brik/exterior/techrash.lua b/assets/game/mode/brik/exterior/techrash.lua
new file mode 100644
index 00000000..6018e56f
--- /dev/null
+++ b/assets/game/mode/brik/exterior/techrash.lua
@@ -0,0 +1,22 @@
+---@type Techmino.Mode
+return {
+    initialize=function()
+        GAME.newPlayer(1,'brik')
+        GAME.setMain(1)
+        playBgm('way')
+    end,
+    settings={brik={
+        seqType='bag7p7p2_power',
+        event={
+            playerInit=mechLib.brik.techrashChallenge.event_playerInit,
+            always=mechLib.brik.techrashChallenge.event_always,
+            afterClear={
+                mechLib.brik.techrashChallenge.event_afterClear,
+                mechLib.brik.music.techrash_afterClear,
+                mechLib.brik.progress.techrash_afterClear,
+            },
+            drawBelowMarks=mechLib.brik.techrashChallenge.event_drawBelowMarks,
+            drawOnPlayer=mechLib.brik.techrashChallenge.event_drawOnPlayer,
+        },
+    }},
+}
diff --git a/assets/game/mode/brik/exterior/techrash_easy.lua b/assets/game/mode/brik/exterior/techrash_easy.lua
deleted file mode 100644
index 7be80d8a..00000000
--- a/assets/game/mode/brik/exterior/techrash_easy.lua
+++ /dev/null
@@ -1,22 +0,0 @@
----@type Techmino.Mode
-return {
-    initialize=function()
-        GAME.newPlayer(1,'brik')
-        GAME.setMain(1)
-        playBgm('way')
-    end,
-    settings={brik={
-        seqType=mechLib.brik.techrashChallenge.easy_seqType,
-        event={
-            playerInit=mechLib.brik.techrashChallenge.easy_event_playerInit,
-            afterLock=mechLib.brik.techrashChallenge.easy_event_afterLock,
-            afterClear={
-                mechLib.brik.techrashChallenge.easy_event_afterClear,
-                mechLib.brik.music.techrash_easy_afterClear,
-                mechLib.brik.progress.techrash_easy_afterClear,
-            },
-            drawInField=mechLib.brik.techrashChallenge.easy_event_drawInField,
-            drawOnPlayer=mechLib.brik.techrashChallenge.easy_event_drawOnPlayer,
-        },
-    }},
-}
diff --git a/assets/game/mode/brik/exterior/techrash_hard.lua b/assets/game/mode/brik/exterior/techrash_hard.lua
deleted file mode 100644
index d7540af7..00000000
--- a/assets/game/mode/brik/exterior/techrash_hard.lua
+++ /dev/null
@@ -1,21 +0,0 @@
----@type Techmino.Mode
-return {
-    initialize=function()
-        GAME.newPlayer(1,'brik')
-        GAME.setMain(1)
-        playBgm('way')
-    end,
-    settings={brik={
-        event={
-            playerInit=mechLib.brik.techrashChallenge.hard_event_playerInit,
-            always=mechLib.brik.techrashChallenge.hard_event_always,
-            afterClear={
-                mechLib.brik.techrashChallenge.hard_event_afterClear,
-                mechLib.brik.music.techrash_hard_afterClear,
-                mechLib.brik.progress.techrash_hard_afterClear,
-            },
-            drawBelowMarks=mechLib.brik.techrashChallenge.hard_event_drawBelowMarks,
-            drawOnPlayer=mechLib.brik.techrashChallenge.hard_event_drawOnPlayer,
-        },
-    }},
-}
diff --git a/assets/language/lang_en.lua b/assets/language/lang_en.lua
index 0ad80fc8..fd9dbe9b 100644
--- a/assets/language/lang_en.lua
+++ b/assets/language/lang_en.lua
@@ -203,8 +203,7 @@ local L={
     -- Mode name
     exteriorModeInfo={
         marathon=              {"Marathon","Clear 200 lines with acceleration"},
-        techrash_easy=         {"Techrash Easy","Clear as many Techrashes as you can"},
-        techrash_hard=         {"Techrash Hard","Clear as many Techrashes as you can, but not too close together"},
+        techrash=              {"Techrash","Clear as many Techrashes as you can, but not close to previous ones"},
         hypersonic_lo=         {"Hypersonic LO","Hypersonic\nHello World"},
         hypersonic_hi=         {"Hypersonic HI","Hypersonic\nSerious Challange"},
         hypersonic_ti=         {"Hypersonic TI","Hypersonic\nVelocital Trepidation"},
diff --git a/assets/language/lang_zh.lua b/assets/language/lang_zh.lua
index 28892548..33f764fb 100644
--- a/assets/language/lang_zh.lua
+++ b/assets/language/lang_zh.lua
@@ -203,8 +203,7 @@ local L={
     -- Mode name
     exteriorModeInfo={
         marathon=              {"马拉松","在逐渐加速下消除200行"},
-        techrash_easy=         {"消四-简单","做出更多的消四"},
-        techrash_hard=         {"消四-困难","做出更多的消四，但不能靠太近"},
+        techrash=              {"消四","做出更多的消四，但位置不能重复"},
         hypersonic_lo=         {"超音速-易","瞬间下落\n新世界"},
         hypersonic_hi=         {"超音速-难","瞬间下落\n严峻挑战"},
         hypersonic_ti=         {"超音速-钛","瞬间下落\n极速恐慌"},
diff --git a/assets/scene/app_piano.lua b/assets/scene/app_piano.lua
index 021b5f76..15c63e6c 100644
--- a/assets/scene/app_piano.lua
+++ b/assets/scene/app_piano.lua
@@ -22,7 +22,7 @@ function scene.enter()
 end
 
 function scene.touchDown(x,y,k)
-    -- TODO
+    -- TODO: cool piano
 end
 scene.mouseDown=scene.touchDown