INTRODUCTION: Several digital games that aim at developing computational thinking in children have emerged in the last few years, as the importance of such ability is increasingly being recognized. Nevertheless, there are no appropriate methods to determine the quality of these games, which hinders their adoption in formal education settings. OBJECTIVES: The general goal of this research is to contribute to the development of a specific evaluation method for children's games that involve computational thinking. In this sense, the specific objective of this paper is to identify which pedagogical and technical aspects of children's interaction with this type of game are proved relevant for developing computational thinking. METHODS: An analysis of two games based on the logic of programming was performed through empirical observation of children's exploratory interaction, in the light of heuristics for interface usability, consisting thus of a combination of formative and objective evaluation. RESULTS: Analysis showed that the game's environment for experimenting with programming commands and visualizing the consequent effects was not sufficient for effective guidance, revealing the need for a human mediator. The main aspects identified as needing improvement were the forms of instruction provided to the child; the design of visual representations of commands, which embed key logical concepts; the correspondence between children's context and expectations and the games' simulated world. CONCLUSION: Results point to directions for the creation of specific parameters and adapted heuristics for evaluation of games based on programming logic for children. In particular the main open question is how to design a game so that computational thinking concepts are implicit conditions to solve challenges, making the process engaging but above all leading to the construction of complex concepts such as parameterized commands.