If you have a spark the next thing must be your crankcase/chamber pressure. I would say this diagnosis goes along with the engine seeming to have a little life in the way it "carried" you slightly. In your pictures your base gasket looked a little beaten up. Possibly even having some tears near the bolt holes? If that is the case, the pressure is being prevented from building up inside your engine and transferring enough fuel/air into your combustion chamber to produce significant power(but just enough to feel it burn). Also, check to make sure your intake gasket and carburetor/manifold seal are intact and air tight. Lastly, check to make sure both or your carb jets are fully screwed into their appropriate places. Good luck.
Chupa: If your cylinder walls are groove free that is a good sign. However if you have any chips (or cracks) in the cylinder wall it's just a matter of time before the metal surrounding the chip also chips off and compounds your problem. As far as whether or not the engine itself will continue to work depends on the where exactly the metal broke off from (maybe post pics?) and if you have removed ALL of the broken chunks from the inside of your engine. The carb releasing air instead of taking it in sounds like a problem. I would recommend a new cylinder at least, probably with two new rings and maybe a piston head too just to be more safe.
