Laser: range - 7 tiles. 1 ammo. Slow reload speed (maybe like Medic's laser). Deals no instant damage. Target receives 1 dmg per second for 3 seconds. Target could have an emote if it's under the effect similarly to Ninja's stun and Mercenary's poison. If it dies during the effect in any way, it gives the Chemist a sample. Collect 3 samples to get a berserk pill. Show the sample progress when holding laser rifle with broadcast: "Samples collected (x/3)." Cannot collect more samples (and pills) if you already have 2 pills stored.
Hammer: when holding it, broadcast "Berserk pills available (x/2)". Using hammer consumes a pill to go berserk for 7 seconds. During the effect you move 50% faster, are not able to be hooked, are immune to Slug's slime, deal 2x damage, consume no ammo and convert hammer into an insta kill hammer like medic. Also makes laser kill insantly instead of applying 3 damage over time. Can't get samples while under the effect. Broadcast the remaining berserk time during the whole duration. Produce some particle effects to let others know when it's in use and/or change color like Ghoul. If there's at least one pill ready there could be an indicator on the Chemist for zombies and humans to get ready similarly to Scientist's whitehole. After berserk ends have a 3 second cooldown before being able to use it again if player had 2 pills. This is mainly to prevent from accidentally using it again if the Chemist was spamming hammer but also prevents from seamlessly chaining 2 pills one after another for 14 seconds. Instead he might need to step back a little before using it again.
Shotgun: same shotgun as Hero but without knockback since it could be too oppressing with infinite ammo. Maybe more spread or less range.
Gameplay analysis: Chemist should focus on collecting pills to make use of them when needed. He can either laser zombies and then let them die on teammate's defenses or get them on his own by switching to shotgun and finishing zombies that way. Even with perfect aim, the rate of gaining samples is limited by the low ammo which also makes sure that it's not op with a Hero. Some useful scenarios to use the pill: clearing an area from zombies eg. top of a camp, pushing forward to let teammates have more space, killing a protected Witch, clearing zombies from a dead end to let teammates escape or just saving yourself from dying. When in berserk the main weapon to clear an area would be shotgun. Laser would be useful against zombies healing each other too quickly or just to kill a single zombie faster if it has armor. Pistol with double damage and unlimited ammo would be useful for more range. A berserk Chemist still needs to be careful though since zombies can still hammer him to instantly infect him, especially a boomer or a voodoo. If class is too op then only heavily boost ammo regeneration rate during berserk instead of consuming no ammo at all and/or reduce berserk duration. The class isn't very noob friendly as some noobs wouldn't be able to collect a single pill before dying. It should still be an achievable task for most of them but even without pills, Chemist can still act as a budget Hero. In comparison, noob Ninjas jump to slash a target frozen in the open and always die or just sit behind defences and throw flashes. So while the Chemist has a high skill potential it can still be somewhat useful when rolled by a noob by choosing random. And as long as they focus on living they can collect a pill before dying. Regarding the class's usefulness when played by a pro: there is a high potential for game-making plays but clearing an entire area with zombies and a Witch shouldn't happen very often. No shotgun knockback means it's still very easy to get killed when in berserk especially if surrounded. A large clump of zombies healing each other can survive shotgun spam and laser rifle is too slow to kill an entire group. There's a high-risk option of going for hammer kills in such a case though. The Chemist can communicate with team members to help him clear zombies eg. another Chemist, a Ninja or a Hero. The difference between this class's role and whitehole: it should be easier to collect a pill than to get a whitehole. Berserk is also more versatile allowing to kill zombies that are more spread out. For example let's say there is a Witch on top of damascus tower and the whole top half of the tower has zombies going down. A Scientist would either need to use whitehole low for a few of the zombies going down without killing the Witch or somehow get up avoiding the zombies and kill the Witch with whitehole but then he leaves the few zombies going down who can kill his teammates. The latter play is way harder to do anyways. A Chemist could instead go up the tower and kill anyone on his way and then still kill the Witch on top clearing the whole area. A whitehole usually doesn't catch every zombie in the area and doesn't really open up a path. It can stall zombies from going in but there are usually some zombies waiting around the whitehole and once it disappears the situation is still the same. The white hole also doesn't instantly kill and any zombie stuck in it is still a threat that can be hard to get rid of. Especially when multiple zombies are hammering each other. A Chemist has a much higher chance to kill most zombies or at least make them retreat.
Counterplay: zombies hit by the laser should try to survive. They can also focus on pushing somewhere where there's no Chemist profiting from their deaths. They could also bait out the laser shot and then retreat to wait out the 3 seconds before going in again when Chemist has no ammo eg. into a Scientist mine to push. Once zombies see that a Chemist has a pill ready and are in a situation where he might use it, they can cover their flanks from where a Chemist could try to enter to catch him off guard. Especially when going through the main way would be too risky for the Chemist eg. in narrow passages like the 2 tile tunnel on top of newdust. He could try to jump from top and enter from the middle left entrance. Instead a zombie can wait there for him and try to kill him or at least prevent him from entering safely or stalling a few of his berserk seconds. When there's already a berserk Chemist killing zombies they can wait around corners to avoid line of sight to try to jump on him or at least make him more wary and waste some of his berserk time. So zombies shouldn't feel powerless against a berserk Chemist.
Chemist
Pistol: normal pistol
Laser: range - 7 tiles. 1 ammo. Slow reload speed (maybe like Medic's laser). Deals no instant damage. Target receives 1 dmg per second for 3 seconds. Target could have an emote if it's under the effect similarly to Ninja's stun and Mercenary's poison. If it dies during the effect in any way, it gives the Chemist a sample. Collect 3 samples to get a berserk pill. Show the sample progress when holding laser rifle with broadcast: "Samples collected (x/3)." Cannot collect more samples (and pills) if you already have 2 pills stored.
Hammer: when holding it, broadcast "Berserk pills available (x/2)". Using hammer consumes a pill to go berserk for 7 seconds. During the effect you move 50% faster, are not able to be hooked, are immune to Slug's slime, deal 2x damage, consume no ammo and convert hammer into an insta kill hammer like medic. Also makes laser kill insantly instead of applying 3 damage over time. Can't get samples while under the effect. Broadcast the remaining berserk time during the whole duration. Produce some particle effects to let others know when it's in use and/or change color like Ghoul. If there's at least one pill ready there could be an indicator on the Chemist for zombies and humans to get ready similarly to Scientist's whitehole. After berserk ends have a 3 second cooldown before being able to use it again if player had 2 pills. This is mainly to prevent from accidentally using it again if the Chemist was spamming hammer but also prevents from seamlessly chaining 2 pills one after another for 14 seconds. Instead he might need to step back a little before using it again.
Shotgun: same shotgun as Hero but without knockback since it could be too oppressing with infinite ammo. Maybe more spread or less range.
Gameplay analysis: Chemist should focus on collecting pills to make use of them when needed. He can either laser zombies and then let them die on teammate's defenses or get them on his own by switching to shotgun and finishing zombies that way. Even with perfect aim, the rate of gaining samples is limited by the low ammo which also makes sure that it's not op with a Hero. Some useful scenarios to use the pill: clearing an area from zombies eg. top of a camp, pushing forward to let teammates have more space, killing a protected Witch, clearing zombies from a dead end to let teammates escape or just saving yourself from dying. When in berserk the main weapon to clear an area would be shotgun. Laser would be useful against zombies healing each other too quickly or just to kill a single zombie faster if it has armor. Pistol with double damage and unlimited ammo would be useful for more range. A berserk Chemist still needs to be careful though since zombies can still hammer him to instantly infect him, especially a boomer or a voodoo. If class is too op then only heavily boost ammo regeneration rate during berserk instead of consuming no ammo at all and/or reduce berserk duration. The class isn't very noob friendly as some noobs wouldn't be able to collect a single pill before dying. It should still be an achievable task for most of them but even without pills, Chemist can still act as a budget Hero. In comparison, noob Ninjas jump to slash a target frozen in the open and always die or just sit behind defences and throw flashes. So while the Chemist has a high skill potential it can still be somewhat useful when rolled by a noob by choosing random. And as long as they focus on living they can collect a pill before dying. Regarding the class's usefulness when played by a pro: there is a high potential for game-making plays but clearing an entire area with zombies and a Witch shouldn't happen very often. No shotgun knockback means it's still very easy to get killed when in berserk especially if surrounded. A large clump of zombies healing each other can survive shotgun spam and laser rifle is too slow to kill an entire group. There's a high-risk option of going for hammer kills in such a case though. The Chemist can communicate with team members to help him clear zombies eg. another Chemist, a Ninja or a Hero. The difference between this class's role and whitehole: it should be easier to collect a pill than to get a whitehole. Berserk is also more versatile allowing to kill zombies that are more spread out. For example let's say there is a Witch on top of damascus tower and the whole top half of the tower has zombies going down. A Scientist would either need to use whitehole low for a few of the zombies going down without killing the Witch or somehow get up avoiding the zombies and kill the Witch with whitehole but then he leaves the few zombies going down who can kill his teammates. The latter play is way harder to do anyways. A Chemist could instead go up the tower and kill anyone on his way and then still kill the Witch on top clearing the whole area. A whitehole usually doesn't catch every zombie in the area and doesn't really open up a path. It can stall zombies from going in but there are usually some zombies waiting around the whitehole and once it disappears the situation is still the same. The white hole also doesn't instantly kill and any zombie stuck in it is still a threat that can be hard to get rid of. Especially when multiple zombies are hammering each other. A Chemist has a much higher chance to kill most zombies or at least make them retreat.
Counterplay: zombies hit by the laser should try to survive. They can also focus on pushing somewhere where there's no Chemist profiting from their deaths. They could also bait out the laser shot and then retreat to wait out the 3 seconds before going in again when Chemist has no ammo eg. into a Scientist mine to push. Once zombies see that a Chemist has a pill ready and are in a situation where he might use it, they can cover their flanks from where a Chemist could try to enter to catch him off guard. Especially when going through the main way would be too risky for the Chemist eg. in narrow passages like the 2 tile tunnel on top of newdust. He could try to jump from top and enter from the middle left entrance. Instead a zombie can wait there for him and try to kill him or at least prevent him from entering safely or stalling a few of his berserk seconds. When there's already a berserk Chemist killing zombies they can wait around corners to avoid line of sight to try to jump on him or at least make him more wary and waste some of his berserk time. So zombies shouldn't feel powerless against a berserk Chemist.