Thanks for the comments, yes time was my enemy on this one and the spawn bug was very annoying (due to a tick event I had used causing problems with update and overriding my transform position). Found it too late unfortunately!
I'd also gone with the random mesh and spent too much time working out how to do the craters on bomb impact. Which was fun to learn and do but then found out it didn't work in WebGL so that was a bit of a wasted effort! Thinking back that was 2-3 hours I could have used to bug fix and resolve issues with the game.
I really wanted to do this jam to teach myself to finish a game, in that respect I think I did ok (as managed to get the menus, sound and other less interesting bits done) however the testing and fixing part I didn't leave enough time for.
Lession learnt!
Thanks again.