Story - Fresh & new, engaging, entertaining.
Characters - Quite good.
Making - Great.
They showed a different way of time travelling which is quite good. As a fan of time travel genre, I would say the story has some solid fresh elements. Not to mention, no such work in Bangladesh took place till date. The time loop was perfect, although time traveling was not. Overall, I enjoyed it.
Yet, it has several plotholes-
1. Time travel idea with dead body's blood was wrong. Any living person's DNA has the information of the events they witnessed. Their own body possess the information of that speicific day in the past. Therefore taking blood of that dead girl is unnecessary. Let aside taking blood from a dead animal full of germs.
2. Chanchal's character lives in a rented house. How can you build such a tunnel and a secret lab in a rented apartment? What about the landlord? How did you manage to get the space to build such spacious secret place?
3. What about the time travel in 1960s? They need their own body to travel in the past. The cannot do it in any way with this time travelling method.