I have a thriller I am writing, but have never been satisfied with the last half and keep changing it. I figured out what the problem is after breaking everything down and looking it over. When it comes to these types of cat and mouse thrillers, the MC will have a plan on how to get the villain, then the plan will backfire, but then the MC will find a way through and fix the backfire, and the plan will still work after all. I have a plan, and it can work, but I feel it works too easily and there should be a backfire, before things go his way at the end. Plus if I leave the backfire out, I will have a gap on material, and be too short in screenplay length. I would like to have a backfire, but every backfire I have come up with so far, is not fixable for the MC. Everyone I can come up with will destroy the plan entirely. Is their anything I should keep in mind, structure wise, when coming up with a fixable backfire, so it doesn't seem forced? I asked another writer, and he said that if it's forced, then don't have a backfire. Just let the hero's plan work easily, with no problems. But if I do that, then there is no suspense for the last half, until the climax, cause there was no obstacles that had to be worked through in the MC's plan. It feels too easy, and therefore lacking in suspense. Is their something I could do to add suspense, since adding a fixable backfire is not possible, in any of the plans I come up with for the MC? I am just not sure how to add suspense otherwise, and the last half feels slowed down too much as a result. Plus if anything doesn't go wrong in the plan, resulting in any type of tragedy, then the MC doesn't go through the change and develop how I want him to through. Should I leave any his character development out then as a result of a backfire being forced? Thanks for the input. I really appreciate it.