▁It ▁was ▁followed ▁by ▁the ▁sequ els ▁S entin el ▁ 2 : ▁Earth ▁Def ense ▁( 2 0 0 9 ), ▁S entin el ▁ 3 : ▁Home world ▁( 2 0 1 0 ), ▁and ▁S entin el ▁ 4 : ▁Dark ▁Star ▁( 2 0 1 4 ). ▁ ▁Crit ical ▁reception ▁ ▁S entin el : ▁Mars ▁Def ense ▁ 1 4 8 App s ▁wrote ▁" S entin el ▁is ▁easily ▁one ▁of ▁the ▁best ▁tower ▁defense ▁games ▁in ▁the ▁App ▁Store , ▁and ▁genre ▁fans ▁would ▁be ▁cra zy ▁not ▁to ▁get ▁this ▁one . ▁Bey ond ▁the ▁awesome ▁eye ▁c andy , ▁it ' s ▁a ▁pleasure ▁to ▁play ... oh , ▁and ▁you ▁get ▁to ▁blow ▁al iens ▁to ▁bits . ▁What ▁more ▁do ▁you ▁need ?" ▁App s af ari ▁said ▁" Are ▁you ▁a ▁fan ▁of ▁T D ▁games ▁for ▁the ▁iPhone ? ▁S entin el ▁Mars ▁Def ense ▁from ▁origin 8 ▁is ▁a ▁Tower ▁of ▁Def ense ▁game ▁for ▁the ▁iPhone ▁with ▁amaz ing ▁graphics ▁of ▁rendered ▁environments , ▁to wers ▁and ▁enemies ". ▁ ▁S entin el ▁ 2 : ▁Earth ▁Def ense ▁ ▁S lide To Play ▁said ▁" S entin el ▁ 2 ▁man ages ▁to ▁stand ▁out ▁amid st ▁the ▁crow ded ▁tower ▁defense ▁genre " ▁Touch Ar cade ▁wrote ▁" If ▁you ▁happen ▁to ▁be ▁new ▁to ▁the ▁tower ▁defense ▁genre , ▁S entin el ▁is ▁a ▁great ▁place ▁to ▁start , ▁especially ▁with ▁the ▁current ▁price