Hey Montheponies! Honestly getting to wave 3 is quite an accomplishment in it's own right, I don't even get that far all the time. I'm tracking down some of our top players in the comments via their leaderboard names and trying wrestle some of their secrets out of them. Will report back with my findings 😄
You might already have figured these tips out but here are three things that tend to help me:
1) The corner turret slots might be the best places to start putting turrets as they can often defend a combination of West/North or South/East, whereas the turrets in the middle can really only shoot North or South.
2) The dawn phase is incredibly short (only 20 seconds) so I like to kind of plan out what my dawn phase is going to be before it hits. And since I can at least repair during the attack wave, I usually use the first 7-8 seconds of an attack wave to go around and repair. For example I might go "okay when I make it to dawn, I'm gonna do one round of blackjack and if I win I'll buy a holy water turret in the SouthEast).
3) You can figure out where you are in the game one of three ways: the music, noticing the sun coming up from the bottom of the screen, or looking at the score directly. Score goes up once each second from the start of the game. Each attack wave lasts 60 seconds followed by your 20 second rest phase. So after some playthroughs you can sort of calculate backwards where you are at in the wave, sometimes its just about running for that last 5-10 seconds and staying alive til the sweet rays of dawn vanquish those bloodsuckers!
I hope that's helpful!
P.S In the future we will definitely be implementing some of those features you talked about! I think giving the player the option to not have to start over every run via some type of life system is a great idea 👍