Zezima started playing RuneScape in late June/early July of 2001, after one of his friends from the game Triple Triad X messaged him that he knew of a game that he felt Zezima would never be any good at, RuneScape. Zezima's first 99 skill was Smithing, which he achieved in July 2002, followed by 99 Cooking on 10 November 2002 and 99 Fishing on 30 November 2003. He first achieved the top rank in the hiscores in October 2003, but temporarily lost it when RuneScape 2 was released as he didn't train Runecrafting until Choppermad (who was ranked second at the time) reached level 73 in the skill. He achieved his 20th level 99 in Slayer on 9 July 2005, becoming the first player to attain level 99 in the skill. He obtained level 1980 total on 9 July 2005, and level 2079 total on 4 October 2005, becoming the first player to achieve those milestones as well. At the time of the achievements, these were the highest overall levels a player could obtain. He became ranked top 100 in all skills on 19 March 2006, but has since lost that position.

In June 2007, Zezima became the first person to attain one billion experience overall. After the release of Summoning in January 2008, he lagged behind other players in the hiscores. On his YouTube channel Zezima0213, he stated that he quit playing competitively as the game is "getting progressively easier over time", and that he lost a sense of accomplishment in what he worked hard to achieve.

On 31 August 2013, Zezima attained level 99 Divination, becoming the 18th player to do so. As of 27 January 2016, he has won 12 Seasonal HiScores competitions. He won his first competition, Red Imp Kills, on 6 October 2013 On 21 July 2016, Zezima achieved 200 million experience in all 27 skills, and 5.4 billion experience overall with rank 63 on the hiscores. As of 2014, Zezima is still active and usually plays on world 103.

In FunOrb, a game website run by Jagex, Zezima has over 349 thousand Orb Points (a scoring system on the site), more than any other player as of 24 December 2015.