I made another little game, in game you have to destroy everything around you, well, you can also choose to leave everything untouched. The point is that 100% of the level can be smashed to pieces and you happen to have a hammer.
It became pretty clear that the destruction system as it is currently is not really meant to be used to that extent, there are tons of glitches but it is a lot fun anyway.
- The problem is that I can’t make the whole world physical simulated all the time to save performance which results in things floating in air when something under it has been cleanly destroyed.
- Another problem is a strange bug where at some point some non destroyed objects don’t collide at all anymore (you can move through them) Could be that happens when a lot is destroyed already but it also happened to a few specific objects several times but they were not different to others.
- Destructibles are hardly meant to destroy each other. What I did for the car is to make the front piece with a hit event which does damage but only every 0.1 secs and not to itself BP. Even that resulted in big performance drops.
- “World Support” does not work with destructibles only, they will hold each other in the air without being connected anywhere to a ground. I had to build everything perfectly grid based, no touch but fitting on each other.
- I made the physic simulated hammer make damage on hit event, I had to make the damage amount fixed or values were all over the place (damage amount based on velocity was not working out). I also had to limit the hit event to the swing time otherwise you could just move through everything with your hammer on the front.
- I had problems with the physics animated hammer swinging much slower with a low fps, I tried different solutions to apply force to the physic swing but it remained. I ended up using the experimental physics substeps features in the settings. That seems to mostly fix it.
- There were also crashes but that might be normal for so much physics going on.
- Destruction chunks don’t get destroyed by Kill-Z, they seem to fall just endlessly down. I hope they get resolved at some point, at least it seemed to made not a big performance impact when a lot of the level is already fallen away.
Now I had only 2 days time to make it maybe there are still other workarounds. If you have any more knowledge of it please share it. I would love to make more out of it and I hope Epic will also improve destruction with further Unreal Engine updates. If anyone of Epic likes to have my project for testing/bug hunting just let me know.
I entered the Indies VS PewDiePie game jam with it: http://jams.gamejolt.io/indiesvspewdiepie/games/where-is-my-hammer/39931
Please give it a vote there if you like to see a Unreal Engine game played by the biggest fish on Youtube! 
You can download the game at best here: Where Is My Hammer: Destroy Everything! by Toco Games
If anyone knows what missing dll error is all about that would be great: MSVCR120.dll is missing Error - Platform & Builds - Epic Developer Community Forums
