Can I replay stages in Mega Man X?
Can I replay a stage in Mega Man X after defeating the robot master?
I missed a heart tank upgrade in Armored Armadillo's stage. If I defeat the boss and finish the stage, will I be able to come back later for the upgrade?
Yes, you can always reenter the 8 main maverick stages in Mega Man X along with the other Mega Man X games. Reentering stages multiple times is actually required to get 100% completion.