It was quite engaging at first, having to pause and make decisions but it’s not as interesting after a while because it’s all about raising the numbers to out-damage or out-heal the enemy. Even though it can be thought-provoking to choose between ranged, melee and defense, there’s not enough mechanics or variety to stay engaged until Level 100. I feel that the pacing needs to be improved as it becomes too much of a drag to start over. Unlike a rogue-like game, there’s no random generation or variety to make the restart from zero interesting - there are no new circumstances different enough to discover, so restarting from Level 80 for example, would be extremely discouraging. Hence, there needs to be some incentive or motivation for the player to try new things when they fail. As terrible as this sounds, consider adding checkpoints with maybe a little boss every 20 levels, and have a practice mode where players can try out builds safely. Perhaps the character that they built can carry over after death, and lose some of their progress but not all - or perhaps even have multiple characters with the option to flee and come back another time.
Overall, I had some fun planning and calculating the build for my character in this game and there’s definitely some potential there. Good job!