Mark of the Ninja: Remastered

Each level has 9 objectives to do for achievements and skills points to buy abilities.
3 are optional objectives you can read about in pause menu.
3 hidden scrolls which includes a challenge room... And finally..... 3 stars which you obtain by reaching the 3 scores thresholds in the pause menu.

After each stage you beat new skills become available for purchase with skills points. You will be able to achieve this towards the last few stages when your are able buy them all. This includes the "bonus stage" Dosan's Tale. From the level select screen you have to hit cn_RT to select this level and play it.