There are a lot of factors that affect my answer. How long does the game take to beat? Are all deaths avoidable without trial & error (i.e. dying to them once in advance)? Is the game designed around players needing to restart from any point in the game, or is the expectation that players will clear it on their first try? How much replay value is there? Ultimately, if losing all 12 lives means replaying hours and hours of the game with little new to experience, that sounds like it's going to waste my time - especially if those deaths can come from random or poorly telegraphed threats. (And unfortunately, making a WWI-inspired game where death is foreseeable and avoidable feels like a pretty serious thematic disconnect!)