Alchemist is a monster of a hero if played right. He has a ranged stun, his acid does a deceptively large amount of damage, he can lack creep kills and have the same items as you, and he can regenerate his missing HP in a jiffy. This is Alchemist in a nutshell, he does, however grow more complicated. Timing and placement of your skills is more important than with any other hero on Alchemist, in my opinion of course.
Extra gold from farming
Long ranged, high duration stun
Hard to kill
High reward for players that are competent
Low CD ult
Stun can backfire
Very weak without rage on
Susceptible to aggressive play in lane
Acid Spray is a damage over time AOE spell. At max level it will do 32 damage in the area and last for 16 seconds. All this together will round up to be 512 damage IF a single enemy were to stay in the AOE the entire time. It should probably be damaging more than just a single unit, to get the maximum DPS. Keep in mind, I haven't even accounted for the armor reduction. If placed right in a teamfight, it can be an amazing tool. Can also be used to kill a creep wave.
Long ranged stun, and it does decent damage when leveled. Of course there is more to it than that, and this is where timing of abilities comes into play. The duration of the stun and damage increases as the 7 second timer decreases. If the timer hits 0, it backfires and you receive damage and get stunned. Use this wisely! If you get stunned while timer is low, you just gave them a double-stun on you.
goblin's greed Self explanatory. You get extra gold for every creep you kill, and you get even more gold for each successive creep kill. This is why you should really be good at farming, because if you can land all the last hits in a creep wave, then that is 28 extra gold per wave. Plus, it can carry over to the next wave starting at the 8 bonus gold. Seriously, getting core items and luxury items is quick.
The primary trait with this ability is the health gain and mana+HP regen. It's why Armlet works so well with this ult. Added bonus is you get more attack speed, and movement speed boost, and it has a really low CD meaning you can just use it for sustain in lane so you can continue farming!
Alchemist is pretty diverse, in that he can really do completely different things in the early game.
If you plan on pushing hard early, grab points in Acid Spray before the others.
If you plan on farming all day, grab points in goblin's greed before the others.
If you plan on ganking a lot or having decent lane control, grab points in Unstable Concoction before the others.
Mix it up to your liking, depending on what you plan to do.
For Alchemist, I like to build on what he already has going for him. This build makes it so that you remain weak early game, but after your core you are capable of tanking lots of damage, as well as dealing a great amount of damage.
Starting, Quelling Blade is really going to help your farm. Stout Shield is also a perfectly good choice.
I usually just grab a ring of regeneration as soon as I can in lane, it will allow you to stay in lane without the need for a Tango or Healing Salve. If all is going well and you aren't getting harassed much, save up for either Ring of Health or Helm of Iron Will. If the enemy is harassing a lot, grab another ring of regeneration. As soon as you can, build a Hood of Defiance. The HP regen helps a lot, and being a "in your face" kind of hero, you will have spells blown on you. After that, grab your armlet. This isn't an expensive build, but it is damned effective. Just farm until you have these two items, then you are a force to be reckoned with. Before hand, you are weak. Just farm until you can afford these, if you have enemies playing aggressively, it will take even longer to farm your core, which is a pain in the ***.
This is where your build will root out. Depending on your enemies, different items will be better in certain cases. This will also depend on your role in the team.
Of course, Alchemist wouldn't be Alchemist if he didn't have choices! My current build I have showed you leaves you a little weak on attack early but, but emphasizes on getting regeneration and survivability early on. Let's talk about some alternate item builds...
Once you have a core item, or preferably both, this should mark your "mid game". The way this build goes really encourages you having both items before you leave lane. At the bare minimum, have one before you start going out and ganking. If you do plan on ganking, take some extra points in Unstable Concoction. Alchemist is an amazing ganker, simply for the fact that once the enemy sees you, your timer is already down to 1 second and they just got one hell of a stun to the face.
If the rest of the team is not in need of ganks, just stay and lane and farm. After level 6 you really shouldn't have too much trouble with anything. Just work on keeping yourself farmed well, because you are very item dependent.
If your team wants to coordinate a push on a tower, you can really help out here. Laying down your Acid Spray will take out the enemy creeps fast, resulting in a quick, clean push.
Here you will be coordinating pushes and fights with your team. Try to have some items other than your core, if you have done well you will be farmed pretty well and everything should go smoothly on your part.
Where all other Alchemists fail. But you? No. You are going to do good, because you are not a failure like all those other idiotic Alchemists. Right?
The one problem with Alchemist is having your Unstable Concoction backfire on you. A well coordinated team will silence you or stun you right before you throw it, at then you have a nasty 4 second stun on yourself, and this can result in an entire team fight turning around. Try not to even use Unstable Concoction unless you are chasing down an enemy or starting a fight.
At the start of a fight, try to find the most concentrated area of enemy heroes and lay down Acid Spray.
Right when the fight starts, use your Chemical Rage.
There may come a time where you get caught by yourself against an enemy or enemies you cannot escape from. At this point you may want to try a small tactic: suicide. If you can time it right, your Unstable Concoction can kill yourself, denying enemies your gold reward.
Thanks for viewing my guide, and please feel free to criticize me! Did I leave anything out? If so, what? Are there any points in here you feel are incorrect? Does the guide just need polishing and more meat to it? Don't be shy!
12/18/2011 - Guide Created