User blog comment:Qwertyxp2000 the second/BTD6 upgrade ratings!/@comment-36139626-20180805210404/@comment-25404524-20180806042025

I suppose the Shimmer upgrade is great on cornered maps, but usually I have pretty good Camo detection anyway, rendering this upgrade less useful. But I still use this upgrade at times when I feel I am overcrowded with camos, especially Camo Leads which my defenses normally can't do in a track without water. If there is water, however, I'd for sure add the Submerge and Support as well as 0/2/x Buccaneers. For sure Submerge and Support is more reliable overall against camos.

So overall, I typically don't use this Shimmer upgrade very much, but when I do it's only when there's no water. Shimmer does great overall coverage, but the reload speed for the anti-camo shimmer is really slow, which does terribly in non-cornered areas. I did have some good use for Shimmer on other uses though.

As for Necromancer, besides lag when spamming Necromancers, the Necromancer does a reasonable job against rounds that have multitudes of bloons.

And with Really Big Bombs, I don't know why I found the Really Big Bombs "good" because I thought it was great only because it was the precursor to the Bloon Impact. In fact, I think Really Big Bombs is a "meh" upgrade, because it at least does what it's supposed to do for its price but it's not a really draining waste upgrade like some upgrades.