One thing I shall say for the Sharknado films: they're mercifully short at 80 minutes usually.
The other thing I'd say is they are entertainingly silly movies - so bad they're good.
Lots of laughs, esp references to other films like ET and the Wizard of Oz and more.
The end promises a 6th outing for the sharks - which will seemingly be like Back to the Future with time travel, Yikes!
This Sharknado manages to travel the world (on film sets at least), starting in a very fake Stonehenge where its absurd plot starts, then London which is fun to watch as well - though the actor playing the Prime Minister has perhaps the worst British accent ever, and as for the Queen...
Then we go to Switzerland, Paris, Germany, Australia, Kansas, LA, Japan...
Total nonsense - but then so are so many Hollywood films which have no self-awareness.
Sharknado knows it's absurd - so bad that it's good - and that makes it fun.