gistfile1.cs

        public IEnumerable<Game> GetAppInfos(params string[] appIds)
        {
            var response = _httpClient.Get(API_ENDPOINT + string.Join(",", appIds)).StaticBody<Dictionary<string, StoreApiResponse>>();

            foreach (var id in appIds)
            {
                yield return _parseGame(response[id], id);
            }
        }

        private Game _parseGame(StoreApiResponse appInfo, string appId)
        {
            if (!appInfo.Success) return new Game {Success = false};
            const string MultiPlayerId = "1";
            const string CoopId = "9";

            var categories = appInfo.Data.Categories;
            var coop = categories.Any(x => x.Id == CoopId);
            var mp = categories.Any(x => x.Id == MultiPlayerId);

            return new Game {AppId = appId, Coop = coop, Multiplayer = mp, Name = appInfo.Data.Name};
        }

        class StoreApiResponse
        {
            public bool Success { get; set; }
            public StoreApiData Data { get; set; }
        }

        class StoreApiData
        {
            public List<StoreApiCategory> Categories { get; set; }
            public string Name { get; set; }
        }

        class StoreApiCategory
        {
            public string Id { get; set; }
        }