Weapon weight
Different weapons have different weights now and affect the ship speed differently. Machine Gun (1), Laser Gun (2), Shotgun (3), Rocket Launcher (3), Electric Gun (4) and Grenade Launcher (4)
The weight is visible in the weapon info:

Special weapons
Added new special weapon - EMP: deactivate nearby enemies temporarily.
Changed special weapon - Mine: four mines are now laid (instead of only one) and the mines stay alive for a longer amount of time. Damage amount and damage radius for single mines have been reduced.
Changed special weapon - Cluster bomb: the bomb now splits into five parts (instead of three). Total damage is higher when the bomb has been split.
Ship model selection
There are now four different ship models to choose from at game start:

