Thanks for the info @jefeesdios - currently grinding to get more boosters and manage to get to lvl 23 catronauter. I'm glad it is achievable even if leveling up after that seems pretty hardcore again :l
Just finished lv20. Lv21 was easy, collect 500 000 000 000 hearts, reach lv10 with 11 kitties, and something about blacksmith (but couldn't see because of the collect rewards button). I got a new cat for that : Dust Bin. Trying to complete lv22 : collect 3 333 active boosters, reach lv23 castronauter, reach lv10 with 7 uncommon kitties.
I think reaching castronauter lv23 is going to be a drag so currently just grinding to get boosters.
@randomlivez I think Taxicat comes after Saber. I haven't got all the cats, far from it, but I seem to remember he comes after Saber. I also have a feeling you need to get a special basket to unlock the legendary cats.
@jefeesdios I'm currently on x87.4 - I have tried reseting and cumulating more multipliers but I haven't found it to be that useful when it comes to reaching certain objectives (such as Paleontologist lvl 21). It could be the way to go, I just tend to find it frustrating as my cats level up faster and the quest still seems to take ages ...
@jefeesdios it took me ages to get Paleontologist to level 21 but if I remember correctly the next levels are easier to achieve. I'm now stuck on level quest 20 trying to get Train Conductor to level 20 (which is taking me weeks and weeks). I have 19 cats, I don't think you get one every time you level up, it's been every other level for me (but not having gone up a level in a while I may not remember correctly). This game just takes ages and there isn't much to be done about it apart from using Taiyaki to speed specific actions up (but will still take for ever :l )
@Dankaw : I'd be very interested in a guide to better my progress if ever you feel like making one. I do enjoy the game but I feel I'm not progressing that fast ...