I used to be able to complete super Mario land on the Gameboy in 90 minutes. I think game time is something people focus too much on. some people only buy games if the single player mode is longer than 20 hours, I think final fantasy 7 took hundreds of hours to complete, but I think that was too much.
I think you're good to release it with 30 minutes of levels then add more later with updates. Then if it gets popular them do some themed level packs as IAP.
I think you're good to release it with 30 minutes of levels then add more later with updates. Then if it gets popular them do some themed level packs as IAP.