Stable update r200 fixes a number of bugs and improves performance and reliability, covering a total of 40 changes. For the full details see the intervening changelogs:

r196 (11 changes) and r196.2 (4 changes): asm.js physics update, renamed ?node-webkit? references to ?NW.js?, performance improvements
r197 (8 changes): more asm.js physics updates; bug fixes
r198 (9 changes): Tilemap bar zoom option, bug fixes and reliability improvements
r199 (8 changes): more bug fixes
New physics engine
The biggest new feature since r195 is that the asm.js physics engine has finally been updated and has all the same features as the old box2dweb engine, including "disable collisions". It is now the new default physics engine. Box2dweb is still available for backwards compatibility, but is not recommended and will not be maintained any further. We recommend wherever possible that existing projects switch to asm.js physics to take advantage of improved performance.

Construct 3 is now in development
In other news note that Construct 3 has been announced. You can stay up to date with the latest news at Construct3.com. While Construct 3 is a long way off, note that a consequence of its development is that the Construct 2 update cycle will slow down.