Hey thank you for playing the game, I'm assuming that if you played the experimental version then you are already on our Discord server.
About your suggestions:
1. To quit a run you can use the "K" key for now and in version 1.3 there will be a proper button.
2. v1.3 will have a lot of new enemies (v1.2 - 8 enemies, v.1.3 - ~40 enemies) to give variety to the game. After round 60, I intend to cycle the enemies again with exponentially increasing stats.
3. Purple turtles were supposed to drop embers as well but I forgot to add that feature.