Once Wesker became infected with Prototype virus, the only physical change he had was in his eyes, whose pupils narrowed and took on the appearance of slits while the color changed to a yellow or red hue. In addition, his eyes also developed a form of periodic bio-illumination, glowing a deep shade of red whenever he felt an intense emotion, such as anger. Exposure to this virus also has led Wesker to lose any trace of humanity he has ever had and to become more self-centered than before.
After his massive exposure to Uroboros virus, while Wesker's lower body remained human, the upper became grotesque and bizarre, as the resulting mutation gave rise numerous undifferentiated tentacles sprouted that completely enveloped his torso and limbs. All tentacles were linked by the orange pustule-like organs that emerged in the center of his chest and back, which served as the control center of the organic growth. At the same time, several dark spots similar to burns appeared over most of Wesker's torso, face and forearms. Uroboros also seems to have made Wesker's mentality insane, causing him to act bestial and talk all the time about natural selection, social Darwinism and his hatred of the human race.
Prior to his exposure to Progenitor Virus, like the other Project W test subjects, Albert had certain special genes considered "superior" in his blood that made him immune to viral infections symptoms.
After his infection with Prototype virus, due to increased metabolism in his body, Wesker had gained a number of physical attributes above normal human parameters. His physical strength growted so much that he was capable intercept and throw missiles with hand, lift steel girders off his body, and kill a B.O.W. with one strike. Wesker's resistance was also amplified, such as magma can't burn him directly and thousands of pounds of steel falling on him from only dazed him for a few seconds. His speed and reflexes are perhaps his most notable skills. He doesn't get shot at close range perform short dashes of speed faster than the brain could comprehend, giving him the appearance of teleporting, and leap great heights. The virus also gave him a strong healing factor, as could to regenerate from light to fatal injuries in a short time and has also shown the power to resurrect him from the dead so long as the majority of his body remains intact. Since his resurrection, Wesker's physiology also appears to have stopped from physically aging. However, despite all these attributions, due to the instability of the Prototype virus, Wesker needed to inject himself regularly with serum PG67A/W to keep it under control, otherwise he would have his superhuman abilities stunted. The serum itself needed also be administered in very precise doses so that it would not damage Wesker's body from the inside.
By merging with the Uroboros virus, unlike the other individuals exposed to the virus, Wesker had complete control of its mutations, making it more powerful than before, but led him to a grotesque condition. Through Uroboros' pustules, he could use the tentacles generated by them to attack or grab his targets and could assimilate inorganic material into them, like metal fragments, to further intensify his attacks. He also showed the ability to use electricity with the metal he assimilated. In this state, Wesker's resilience could only be impaired if he were injured in the organs in the center of his chest and back, as seen when he fell in the lava of a volcano after being repeatedly stabbed there by Chris and Sheva in those respective places. However, he still had enough strength to survive the magma of volcano, despite Uroboros' weakness to the intense heat, and managed to grab the BSAA helicopter with one of his tentacles to the point of preventing him from moving away. Overall, it was necessary to hit Wesker with a pair of RPGs to completely destroy him.