i fluctuate between loving this game and hating it, i am doing a bit better by not wasting gems on beacons, shrines, etc, leaving infested buildings intact and just making multiple towers with grade 3+ gems
lvl id 7 & lvl id 8 are very stressful to me, it's hard to find a balance between building towers with gems strong enough to kill monsters and destroying the infested buildings before monsters come out of them