Ehm... this is not about anti-Trust (that's how they call it in the USA btw, in Europe it's Competition law) old art. 81 EC (now 101 TFEU), but abuse of a dominant position old art. 82 EC (now 102 TFEU)
Edit: as I said, it's a question of defining the market, is there a separate market for paradox games or are they part of a bigger market for (strategy) games? And there is also always an aspect of market share that you'll have to take into account when answering these kinds of questions.
Article 102
(ex Article 82 TEC)
Any abuse by one or more undertakings of a dominant position within the internal market or in a
substantial part of it shall be prohibited as incompatible with the internal market in so far as it may
affect trade between Member States.
Such abuse may, in particular, consist in:
(a) directly or indirectly imposing unfair purchase or selling prices or other unfair trading conditions;
(b) limiting production, markets or technical development to the prejudice of consumers;
(c) applying dissimilar conditions to equivalent transactions with other trading parties, thereby
placing them at a competitive disadvantage;
(d) making the conclusion of contracts subject to acceptance by the other parties of supplementary
obligations which, by their nature or according to commercial usage, have no connection with the
subject of such contracts.
Edit: as I said, it's a question of defining the market, is there a separate market for paradox games or are they part of a bigger market for (strategy) games? And there is also always an aspect of market share that you'll have to take into account when answering these kinds of questions.