Is there a chance to extend part 2 for 1 additional day?

Done. Please check the contest page for exact timing.

Thanks+for+the+nice+tests%2C+Riad%2E%0D%0AI+always+love+the+fresh+new+challenges+you+come+up+with%2E%0D%0A%0D%0AHowever+it+seems+your+IB%27s+are+always+quite+difficult+to+read%2E%0D%0ALanguage+barrier+may+be+to+blame%2E%0D%0APerhaps+you+might+want+to+consider+having+the+test+solvers+go+through+some+of+the+IB+wording+next+time%3F%0D%0A%0D%0ASometimes+good+IB+examples+come+to+the+rescue+when+wording+seems+unclear%2E%0D%0AUnfortunately+some+examples+here+don%27t+help+much+either%2E+%28Circles%2C+Pentominoes%2C+Sudoku+without+Sums%2C+Off%2DRoad+were+too+trivial+I+thought%29%2E%0D%0AThe+cube+Samurai+%28a+great+puzzle%29+had+yellow%2Dcircled+cells+that+applied+to+three+puzzles+%2D+which+wasn%27t+clear+if+that+was+the+case+or+whether%0D%0Ayou+had+to+figure+out+which+two+%28out+of+three%29+grids+it+applied+to%2E%0D%0A%0D%0AThese+are+minor+observations+and+does+not+take+away+the+nice+puzzles+you+provided+us%2E%0D%0AThanks+again%2E+%F0%9F%99%8F%0D%0A

Thanks for really nice test, Riad! As always, puzzles are "unusual" and challenging.

Congratulations to Hideaki, Ken and Zimi!

Thanks to all participants!