Smokestack Mountain is full of dangers, not least of them rust beasts! These annoying creatures will attack you on sight, so you'll have to be on your guards at all times.
Rust Wasps
Ugh, these guys. They fly around and shoot at you. You wouldn't believe how annoying they can be. While slow themselves, their projectiles will inflict Power Leakage, a rather painful damage over time. Evade the projectile, and shoot them while they reload!
Rust Spiders
These nasty little guys are expert trappers. As far as rust beasts go, don't let them catch you off guard. They may move slowly, but their web will inflict a debuff slowing down your movement for quite a while. Shoot the web out of your way, then dash in and finish them off with your blade.
Rust Dragonflies
Ah, dragonflies... The way these guys dive-bomb you can be really aggravating. Evade their dash with a jump or a dash of your own, then defeat them with your drill. Or better yet—be fearless and quickly shoot them while they're flying at you!
Rust Rhinos
In Stamp's own words, "not that I have a problem with rushing in headlong, but when a rust beast does it to me, that's a different story..." With Rhinos, patience is key: when they rush at you, the only way to evade is to jump over them. Once their back is exposed, attack them with all you have, preferably with your hammer! Taking them on from the front will only result in heavy damage (for you).
