I posted this on a mix of social media to get discussion on what this plan tell us, using the simple case above to suggest some of the things that large "real" project can show that might be misleading.
What percentage complete is this project
Well from simply looking at the percentage of tasks complete one might guess this project is about 50% complete, maybe even a little more. If you look at it in more depth, you can ask the question how can task 3 have started when it is dependent on task 2 completing. This is where the plan might not be a good model of the real world and to verify the situation you need to talk to the team involved. It is possible that the dependency shown in the plan is incorrect and task 3 can start before task 2 is completed; if that is the case then the plan would need to be amended because it is no longer a good model of the intended path through the project. It could be that the team have simple recorded progress against the wrong task and what was recorded should be reflected in task 1 and 2 and the plan remains a reasonable model of the world.
But just from a quick review it is easy to see that you can form a mistaken picture of a project if you do not look deeper.
Will the project finish on time
This is the key question and the plan in any project will give a picture against whether the project will finish on time. Analysis of the tracking will help give some answers but the plan is only as good as the current understanding of the project, if the knowledge is flawed then the plan will be flawed. Few Projects can expect to finish without some modification to the plan, experience has shown me that all projects of any but the very smallest size will involve some adjustment of the plan. It is the model for success, but a rigid inflexible plan is a model for failure, regardless of your chosen project management method.