It was an absolutely amazing experience! The black and white color composition was a perfect fit for the game in many different contexts (ie the simplicity of the game, black vs white - unreal vs real, etc). To me, it's not old-fashioned at all.
Regarding the gameplay, I played it by myself and enjoyed it a lot. The puzzles were fun and many mechanics could be expanded upon. I particularly loved the jump-boosting mechanic where dino1 jumps on dino2 then I can spam jump on both to boost the upper dino up very high (managed to pass level6 very quickly - not sure if it was by your design or not 😅). On the topic of quick, I thought that the experience might also be benefitted from having a timer. A speed run leaderboard for each level would really challenge the players to explore the game to its fullest.
Overall, amazing game. Well done!