The flotation was heavily over-subscribed and raised £107.5m before expenses, giving the Wakefield-based video games developer a market value of £217m.
The company, which is best known for its hit game Worms, floated with a share price of 165p, and ended the day at 224p.
Founder and chief executive Debbie Bestwick, pictured, said: “We are delighted to have received such strong support from investors.
“Our listing on AIM represents a major endorsement of both our business and our people and we believe that our quoted status provides an ideal platform from which to accelerate our growth ambitions.”
She will retain a substantial shareholding in the company, amounting to around 22 per cent, and LDC, the private equity arm of Lloyds Banking Group, will retain a shareholding of 17 per cent.
Together, the management team and employees will hold around 31 per cent of the company.
The directors said the IPO will enable the company to invest in its future expansion, enhance its profile and incentivise key employees.
Ms Bestwick said the firm is committed to its Yorkshire headquarters and it will keep its head office in Wakefield after the float.
“We absolutely plan to expand Wakefield,” she said. “This float is really important to maintain our independence.”