i did find a bug..that gems too close to the altar, will hit monsters that are actually entering the altar(no dmg received), so if you have one within range, there's a chance that at a swarm level it won't do ANY damage (kind of sux for the levels where you only build 1 tower with 8 amplifiers)
well..i broke the game: i got over 4.5k cash in one run and it didn't add..seems i'm down to 250 $(i had them before the flight). you might wanna check on that 2