Level 100 gaunlet is very poorly designed.
Invasion onslaught was way better as a challenge. Level 100 doom bots is basically overstated enemies with undodgeable skillshots and no mana costs. You can't trade with them and can only stall until you eventually lose your towers. Then the bots rotate for the other towers and start sieging you down. As if that wasn't bad enough, every 2 minutes the bots gain a new buff which fucks you even more. I just loathe the global blinding darts and the death defied passive. Even if you manage to survive for 15 mins you have to take down 100k hp teemo. Due to this only long ranged champions are viable. The worst bots are lux and udyr. Lux is impossible to play against as melee or short ranged with her insane burst damage. Udyr summons jungle camps to fight for the doom bots, including dragon.