Bit of a copy-paste from a thread i made on the Steam forums, but i think it's worth posting anyways in response to the Helios balance changes. However, given Tripwire's previous handling with the Firebug's balance changes, I think it'd be worth commenting on most of the weapons, rather than just the Helios specifically:
Helios
Price reduced to 1500
Ammo reduced to 40+280
Damage increased to 65 (was 40)
Upgrade to Level 1 reinstated
Microwave Gun
Beam impact damage increased to 30 (was 16)
Max ammo decreased to 100+300
Can headshot (Caulk and FT can)
Husk Cannon
Base Damage increased to 120 (was 80)
Max ammo decreased to 20+160
Can spawn ground fires if 2 or more ammo units was consumed (initially required a full charge)
Can Headshot (required for most of Demolitionist's skills)
Flamethrower
Damage increased to 30 (was 18)
Ammo decreased to 100+300
Caulk n' Burn
Damage increased to 18 (was 10)
Ammo decreased to 50+250
Helios
Price reduced to 1500
Ammo reduced to 40+280
Damage increased to 65 (was 40)
Upgrade to Level 1 reinstated
Microwave Gun
Beam impact damage increased to 30 (was 16)
Max ammo decreased to 100+300
Can headshot (Caulk and FT can)
Husk Cannon
Base Damage increased to 120 (was 80)
Max ammo decreased to 20+160
Can spawn ground fires if 2 or more ammo units was consumed (initially required a full charge)
Can Headshot (required for most of Demolitionist's skills)
Flamethrower
Damage increased to 30 (was 18)
Ammo decreased to 100+300
Caulk n' Burn
Damage increased to 18 (was 10)
Ammo decreased to 50+250